Final general pharmacology notes by Obin Abraham Olaka, St. Mary's hospital lacor, Gulu city , northern Uganda

PHARMACOLOGY
FOR
NURSES, MIDWIVES
AND
THEATRE ASSISTANTS
C/N-2.1, C/M-2.1, D/M-2.2, CTA-2.1

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Table of Contents
ACKNOWLEDGEMENTS......................................................................................................................................iii
DEDICATION...........................................................................................................................................................iv
Preface........................................................................................................................................................................vi
INTRODUCTION TO PHARMACOLOGY...........................................................................................................1
INTRODUCTION......................................................................................................................................................1
IMPORTANCE OF STUDYING PHARMACOLOGY.........................................................................................1
DRUG NOMENCLATURE (NAMING OF DRUGS) ............................................................................................2
Chemical name.......................................................................................................................................... 2
Generic name (non proprietary name): ..................................................................................................... 2
Brand names (trade or proprietary name) ................................................................................................. 3
SOURCES OF DRUGS..............................................................................................................................................3
1. Plant source ......................................................................................................................................... 3
2. Animal source: .................................................................................................................................... 4
3. Micro organism ................................................................................................................................... 4
4. Semi-synthetic..................................................................................................................................... 5
5. Mineral source/ Earth sources............................................................................................................. 5
6. Recombinant DNA Technology/Genetic engineering ........................................................................ 6
DRUG DOSAGE FORMS.........................................................................................................................................6
1. Definition of Drug............................................................................................................................... 6
2. Definition of Excipients. ..................................................................................................................... 7
3. Definition of dosage form ................................................................................................................... 7
The need for drug dosage forms:............................................................................................................... 7
Description of common dosage forms. ..................................................................................................... 8
COMMON TERMS USED IN PHARMAOLOGY ..............................................................................................11
PRINCIPLES OF PHARMACOLOGY.................................................................................................................15
1. Pharmacokinetics .............................................................................................................................. 16
Pharmacodynamics.....................................................................................................................................................26
DRUG ADMINISTRATION...................................................................................................................................29
a) Definitions......................................................................................................................................... 29
b) principles/rules of drug administration ............................................................................................. 30
Routes in drug administration ................................................................................................................. 31
General advantages of parenteral route................................................................................................... 39
INTERPRETATION OF PRESCRIPTION..........................................................................................................44
RATIONAL USE OF MEDICINE .........................................................................................................................50
Irrational use of medicines;-.................................................................................................................... 50
Factors underlying irrational medicine use;-........................................................................................... 50
Consequences of irrational medicine use;-.............................................................................................. 51

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CONCEPT OF ESSENTIAL DRUGS....................................................................................................................51
Definition. ............................................................................................................................................... 51
Criteria for selection of essential drugs;.................................................................................................. 51
Advantages/Importance of applying Essential drug concept;................................................................. 52
DOSE AND DOSAGE CALCULATION...............................................................................................................53
Definitions............................................................................................................................................... 53
Desired dose............................................................................................................................................ 55
Concentration .......................................................................................................................................... 56
Calculating the ml to be given................................................................................................................. 56
Drip rates................................................................................................................................................. 59
MEDICATION ADHERENCE/COMPLIANCE..................................................................................................60
WHO definition:...................................................................................................................................... 60
Causes of non-adherence......................................................................................................................... 61
What are the consequences?.................................................................................................................... 63
Solutions to noncompliance .................................................................................................................... 63
CLASSIFICATION OF DRUGS ............................................................................................................................65
1. Prescription classification ................................................................................................................... 65
2. Pharmacological classification............................................................................................................ 65
 Pharmacological or therapeutic effect..........................................................................................................66
 Systems they target. .....................................................................................................................................66
 According to the causative organisms they act against;- .............................................................................66
 Mechanism of action;- .................................................................................................................................66
 Chemical structure of the parent compound;-..............................................................................................67
3. Legal classification.............................................................................................................................. 67
GENERAL REVISION QUESTIONS FOR STUDENTS....................................................................................69
Section a --multiple choice questions...................................................................................................... 69
Fill in the blank spaces............................................................................................................................ 94
Essay questions ....................................................................................................................................... 96

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ACKNOWLEDGEMENTS
The AUTHOR, wish to acknowledge and thank all of the contributors for
their commitment, time and relentless effort in sharing their professional
clinical and academic expertise which has made this manuscript a book. I
also wish to thank the reviewers who have provided us with valuable critique
as I have developed this work. I cannot mention your names one by one but
may God bless the work of your hands

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DEDICATION
To God Almighty
A dedication to my Mother Auma Maricellina.

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COPYRIGHT 2019
TERMS OF USE
This is a copyrighted work of Abraham and Companies, and its licensors reserve all
rights in and to the work. Use of this work is subject to these terms. Except as
permitted under the Copyright Act of 1976 and the right to store and retrieve one
copy of the work, you may not decompile, disassemble, reverse engineer, reproduce,
modify, create derivative works based upon, transmit, distribute, disseminate, sell,
publish or sublicense the work or any part of it without Abraham’s prior consent. You
may use the work for your own noncommercial and personal use; any other use of the
work is strictly prohibited. Your right to use the work may be terminated if you fail to
comply with these terms. The work is strictly prohibited. Your right to use the work
may be terminated if you fail to comply with these terms.

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Preface
This short Handbook for Abraham book of pharmacology 1st
edition, is a
comprehensive yet concise clinical reference designed for use by nursing,
midwifery, theatre assistant students and professionals. Perfect for use
across multiple health care settings, the Handbook presents key note
information on each topic discussed here for emphasis, and a carefully
organized table of content that enables readers to gain quick access to vital
information

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INTRODUCTION TO PHARMACOLOGY
By the end of this chapter, learners should be able to
1. Definitions of terms.
2. Outline the Reasons for studying pharmacology.
3. Explain the different ways of naming drugs. (drug nomenclature)
4. Describe the various sources where drugs can be obtained
INTRODUCTION
Pharmacology is the study of drugs and their interaction with the living
system.
The term pharmacology comes from the Greek word pharmakon meaning
medicine and the suffix-ology meaning study of.
A drug; Is any chemical substance which when administered into a
biological system causes physiological and biochemical change in the
body and intended for use in diagnosis, cure, treatment and prevention of
diseases.
OR
Any chemical substance taken in the body or applied on the surface for the
diagnosis, cure, treatment, and prevention of diseases.
Note that; - all medicines are drugs but not all drugs are medicines
Medicines;-drugs used in the treatment of medical conditions e.g.
antibiotics like amoxicillin. Drug is abroad term which also include all
medicines
IMPORTANCE OF STUDYING PHARMACOLOGY
1. Identify drugs and how they can affect the living things
2. To know the right dosage of drugs and not just quantity

3. Identify and respond to drug interactions, reactions and side effects
and treat accordingly.
4. Know when to use drugs because some conditions do not need drug
therapy.
5. Understand the process of drug intake/administration, absorption,
distribution and elimination
6. Know the application of pharmacology in nursing with regards to the
ten rights of;-
 Right patient
 Right dosage
 Right time
 Right formulation.
 Right site
 Right drug
 Right route
 Right storage.
 Right disposal
 Right equipment
DRUG NOMENCLATURE (NAMING OF DRUGS)
A drug may have three categories of names namely;-
 Chemical name
 Generic name
 Brand name
Chemical name
The chemical name describes the drugs chemical composition and
molecular structure. It is not normally used during prescribing.
For e.g. paracetamol
Chemical name: N-(4-hydroxyphenyl)acetamide)
Generic name (non proprietary name):
Is the name approved by a competent drug body e.g. Food and Drug
Administration (FDA). It is much simpler than the chemical name and is
commonly used in prescribing.
Approved name: Paracetamol or Acetaminophen

Brand names (trade or proprietary name)
The brand name is the copy righted name that is given by the company
manufacturing and selling the drug. For e.g proprietary name for
paracetamol is Panadol.
Example
Chemical name (+/-)-2-isobutylphenyl) propionic acid
Generic name Ibuprofen
Brand name Brufen®
Common examples of generic and brand names
Generic name Brand names
Amoxicillin Amoxil®, Auramox®,
Amoxapen®
Propranolol Inderal®
Paracetamol Panadol®, Kamadol®,
Cetamol®
Salbutamol Ventolin®, Vental®
Diazepam Valium®, Slitizem®
SOURCES OF DRUGS
 Plants
 Animals Natural
 Micro organisms
 Minerals
 Synthetic/ Semi synthetic
 Recombinant DNA technology Artificial
1. Plant source

Plant sources is the oldest source of drugs.
Even now some drugs are derived from plants.
Almost all parts of the plant are used i.e. leaves, stem, back, fruits and roots
Source Plant Drug Use
Leaf Digitalis
Eucalyptus
Digoxin
Eucalyptus oil
CHF
RTI
Bark Cinchona Quinine Malaria
Fruit Opium
Senna pod
Morphine
Anthracine
Analgesic
purgative
constipation
Seed Eserin anticholinesterase Myasthenia
Gravis (M.G)
Flower Rose Rose water Used as tunic
Root Rauwolfia
Serpentina
reserpine A
hypotensive
agent
2. Animal source:
Various organs and tissues of animals are used as source of drugs
Active principles of animal drugs are proteins, oils, fat, enzymes and
hormones.
 Heparin-from mucosal tissues of most animals as an anti-coagulant
 Insulin - pancreas as an anti-diabetic
 Thyroxin- from sheep thyroid.
 Vitamin B12 (cyanocobalamin)-from liver extract as a food supplement)
 Cod liver oil-derived from the liver of cod fish (contains Vit A & D)
 Vaccines- from animal blood e.g Tetanus Toxoid vaccine
 Pepsin- from stomach tissues of animals like cow
 Urine of pregnant women gives Human chorionic Gonadotrophin (HCG)
3. Micro organism
 Bacteria
 Fungi

 Moulds
Drug Microorganism
Penicillin Penicilium notatum (fungus)
Chloramphenicol Streptomyces veneauelace
Griseofulvin Penicillin grisofullivum
Streptomycin Streptomyces griseus
(actinobacteria)
Neomycin Streptomyces fradiae
4. Semi-synthetic
When the nucleus of a drug obtained from natural source is retained but the
chemical structure is altered we call it semi-synthetic.
For e.g. semi-synthetic human insulin (pork insulin), most antibiotics
Synthetic
When the nucleus of the drug from natural source as well as its chemical is
altered. It is called synthetic. (Process done in Pharmaceutical laboratory).
Synthetic source involves organic or inorganic or a combination of organic
or inorganic compounds and more than 90% of drugs are under synthetic
source.
E.g. antipyretics, antihistamines, anticonvulsants, anti-anxiety. Etc.
5. Mineral source/ Earth sources
Many drugs are mineral substances and their compounds
Metals:
Mineral Use
Ferrous sulphate (FeSO4) Anaemia
Magnesium sulphate
(MgSO4)
Purgative, laxative
Sodium bicarbonate
(NaHCO3)
Antacid
Aluminum hydroxide Antacid

Gold (solgana) Anti-inflammatory (Rx of Rheumatoid
Arthritis)
Iodine Antiseptic
6. Recombinant DNA Technology/Genetic engineering
This is a new technique for preparing certain drugs e.g. Human insulin,
insulin analogs, and erythropoietin.
Human insulin and insulin analogs may be prepared by inserting human or
modified pro-insulin gene into E-Coli or yeast and treating the extracted
pro-insulin to form the insulin or insulin analoges
Advantages
 Mass production
 Cost effective
 Less immunological reaction/less antigenic
 Effectiveness can be controlled
 Drug can be obtained in a pure form
Disadvantages
 Well-equipped lab is required
 Highly trained staff is required
 It is a complex and complicated technique
DRUG DOSAGE FORMS
By the end of this lecture, learners should be able to;
1. Define terms- drugs, excipients, dosage forms.
2. Give reasons why drug formulation is necessary
3. Outline the various dosage forms.
1. Definition of Drug.
Is any chemical substance administered to a living system and intended for
use in diagnosis, cure, treatment or prevention of diseases.

2. Definition of Excipients.
Is a pharmacologically inactive substance that is included in the drug
dosage form with the purpose of facilitating drug disintegration,
absorption, streamlining manufacturing, improving taste and
bioavailability.
E.g. glucose, calcium and magnesium salts synthetic dyes and natural
colours from food pigments
3. Definition of dosage form
Is the final form of a drug in which a medicine is prescribed for use by the
patient such as injection, tablets, capsules or syrups.
The need for drug dosage forms:
 To provide a safe and convenient delivery of accurate dosage. E.g.
Tablets, capsules, syrups.
 For the protection of drug from the destructive influence of atmospheric
oxygen or moisture. E.g. coated tablets.
 Prevents local drug irritations or ulcers.
 For the protection of drug from the destructive influence of action of
gastric acids after oral administration. E.g. enteric coated tablets.
 Drug Protection e.g. coated tablets, sealed ampules
 To conceal the bitter taste or odour of drug. E.g. Capsules, coated tablets,
flavored syrups.
 To provide extended drug action through controlled release mechanisms.
 Insertion of drugs into body cavities (rectal, vaginal).
 Many drug dosage form permit ease of drug identification through
distinctiveness of colour, or shape.
TYPES/CLASSIFICATION OF DOSAGE FORMS.
Dosage forms can be in solid, semisolid, liquid or gaseous form.
They are classified according to:
1. Route of administration e.g.
 Parenteral route
 Topical route
 Enteral route
 Inhalation.
2. Physical form e.g.
 Solid
 Semisolid
 Liquid
 Gases.

DESCRIPTION OF COMMON DOSAGE FORMS.
Solids and semi-solids
1. Capsules.
These are preparation of powder or liquid drugs enclosed into two
dishes joined together made of jelly (Gelatin) e.g.
Chloramphenicol, cloxacacilline capsules.
2. Tablets.
These are drugs compressed in a dry solid mass meant to be
swallowed with water or crushed e.g. ibuprofen tablets.
Tablets are formulated as coated or uncoated.
Tablet coatings can serve multiple functions:
 Mask undesirable tastes and facilitate swallowing
 The can provide a means for easy visual identification. To
discriminate one drug from another.
 Enteric coatings are sometimes used to delay dissolution until
tablet passes through the stomach and reaches the duodenum.
3. Suppository.
They are conical in shape with solid base of glycerin or cocoa butter
intended for insertion in to the rectum where it melts at body
temperature, dissolves and exerts a systemic or localized effect.e.g.
 promethazine suppository for nausea, vomiting and motion sickness
 Dulcolax (Bisacodyl) suppository for constipation,
 aminophylline suppository, and rectal paracetamol
4. Cream.
This is a semi-solid emulsions of an oil and water (with the main
ingredient being oil).
5. Implants (pellet)
A sterile small rod or ovoid shaped mass intended to be implanted under
the skin for the purpose of providing the slow release of medication over
an extended period of time.

6. Pessary; are solid medicated preparations designed for insertion into the
vagina where they melt or dissolve. E.g. clotrimazole pessary,
clindamycin.
7. Lozenges(troches)
These are flat solid tablets large in size intended to slowly dissolve in the
oral cavity for localized effects. They have Analgesic and antiseptic
effects .E.g. formaldehyde (phenol, bradsol, etc.), acetaminophen they
are also used for mild upper respiratory infection. Also antihistamines
like chlorpheniramine-(piriton), cetirizine.
8. Ointment.
This is a semisolid preparation of drugs intended for external application
on the skin or mucus membrane. E.g. tetracycline ointment.
9. Powder.
A mixture of fine divided drug particle or chemical substances.
LIQUID DOSAGE FORMS
10. Suspension.
This is a liquid preparation containing with insoluble substances for
internal use e.g. magnesium hydroxide.
11. Emulsion
An emulsion is a suspension in which fat particles are mixed with
water.
12. Lotion.
Emulsions for external applications.
They are intended to be applied on unbroken skin without friction .e.g.
calamine lotion.
13. Enema.
A liquid intended to be injected into the rectum.
14. Syrup.
A concentrated sugar solution in water that may contain a flavoring agent
or drug. E.g. Amoxicillin syrup, Paracetamol syrup.
15. Injection

A sterile pyrogen-free preparation intended to be administered using a
sterile needle and syringe (parenterally).
16. Eye drops.
These are sterile aqueous or oily solutions or suspensions of one or more
active ingredients intended for instillation into the eye. E.g. Gentamycin
eye drop.
Gases.
17. Inhalation Drug droplets, vapour, or gas administered by the oral or
nasal respiratory route via an aerosol or nebulizer
18. Aerosol
This is a pressurized preparation that when activated releases a fine
dispersion of liquid or solid materials in gaseous medium
CLASSIFICATION ACCORDING TO THE ROUTE OF DRUG
ADMINISTRATION
ROUTE OF ADMINISTRATION DOSAGE FORMS
ORAL Tablets, capsules, solution, syrups,
suspension, gel, powder, granules.
RECTAL Suppositories, ointments, creams, and
solutions.
TOPICAL Ointment, creams, pates, lotions, gel
solutions, topical aerosol sprays.
PARENTERAL Injections (solutions, suspensions,
emulsions)
LUNG Aerosols, inhalation sprays
NASAL Solutions, inhalations, gases
EYE Solutions, ointments, creams
EAR Solutions, suspensions, ointments

COMMON TERMS USED IN PHARMAOLOGY
 Pharmacokinetics; is the study of what the body does to the drug
involving; Absorption, Distribution, Metabolism/biotransformation,
Excretion
 Absorption (movement of drug from the site of administration
into the blood stream.
 Distribution- is the movement of a drug from the general
circulation into different organs and fluids of the body
 Metabolism/biotransformation- is the enzymatic alteration of a
drug structure into water soluble substances for excretion
 Excretion- is the removal of drugs from the body. Primary
organs involved is kidney, others (bile, feces, saliva, sweat,
breast milk).
 Pharmacodynamics; is the study of what the drug does to the body.
That is mechanism of drug action.
 Pharmacotherapeutics; is the branch of medicine which deals with the
clinical uses (indications) of drugs and their effects
Or is the study of how drugs are used in the treatment of diseases
 Efficacy:-is the ability of the drug to produce maximal response.
 Potency:-is a measure of how much drug is required to elicit a response.
Response
Log drug dose
B
A C
D
Figure 1 graded dose- response curves for four drugs illustrating different pharmacologic potencies
and different maximal efficacies.

From the graph
 A and B are said to be more potent than C and D because the
relative positions of their dose –response curve along the dose
axis
 Drugs A,C,D have equal maximum efficacy and have greater
maximal efficacy than drug B
Note; the clinical effectiveness of a drug depends not on its potency
but on its maximal efficacy and its ability to reach the relevant
receptors
 Allergen; a substance capable of producing an allergic reaction for
example pollen grains from plants.
 Bioavailability; This is the extent to and the rate at which moiety (drug
or metabolite) enters systemic circulation in a chemically unchanged
form thereby accessing the site of action.
 Pharmacognosy; is the study of drugs of obtained from natural sources
e.g. plants, microorganism and animals
 Drug receptor: - is a specialized cell component located on membranes
that combines with a cell, hormone or drug to alter cellular functions or
mediates its pharmacological action.
 Half-life:-is the time taken to reduce the amount of the drug in the body
by one half during elimination.
Therefore, in each succeeding half-life, less drug is eliminated. After
one half-life the amount of a drug remaining in the body is 50% after
two half-life 25%, after four half-lives the amount of the drug
(6.25%) is negligible regarding its therapeutic effects.
The half-life of a drug depends on its clearance and volume
distribution
 Therapeutic dose. This is the dose between the minimum effective and
the maximum doses which provides the desired effect without toxic
effects.
 Therapeutic index:-this is the ratio of the drug that produces the toxicity
to those which produces clinical response. Therapeutic index is therefore,

a measure of the drug’s safety since the higher the therapeutic index, the
safer the drug.
TI=
𝐓𝐃𝟓𝟎 𝐨𝐫 𝐋𝐃𝟓𝟎
𝐄𝐃𝟓𝟎
TD50=the dose that produces a toxic response in 50% of the
population.
ED50=the dose of drug that is therapeutically effective in 50% of the
population
E.g. zidovudine, amphotericin B, Digoxin, Phenytoin, gentamycin,
lithium.
A B
Sleep
Death sleep Death
ED50 LD50 ED50 LD50
DOSE DOSE
Drug A has a narrow therapeutic index while drug B has a wider
therapeutic index. So drug B is safer than A
R
e
s
p
o
n
s
e
%
R
e
s
p
o
n
s
e
%

 Toxicity: - this is an adverse drug reaction caused by excess drug in the
body. This may be due to excessive dosing or accumulation of the drug.
E.g. ataxia, nystagmus, seizures, coma, heart problems.
 Agonist:-an agonist is a substance that binds to a receptor and activates a
receptor to produce a biological response
 Antagonist:-is a substance that binds to a receptor and prevents a
response.
 Partial agonist:-is a substance that binds to a receptor and causes effects
similar but less than that of a pure agonist.
Full Agonist
Activity (%) partial Agonist
Concentration
 Side effects:-these are expected, well known, undesirable effects of a
drug that occur regardless of the dose. e.g. headache, dizziness, nausea,
insomnia
 Adverse effects: - these are any noxious (poisonous), undesirable and
unintended effects of drug that occur at normal drug doses. Example liver
damage by antibiotics like tetracycline.
 Cumulative effects; is a condition in which repeated administration of a
drug may produce effects greater than those produced by the first dose
 Additive effect; is a drug interaction in which the effect of two different
drugs used in combination is equal to the sum of the two drugs take
separately
 Drug interaction:-this is the alteration of one drug by another. It occurs
when two or more drugs are administered to a patient simultaneously.

Drug interaction may result into either negative effects or positive
effects.
 Synergism: - is a drug interaction between two or more drugs that causes
the total effect of the drugs to be greater the sum of the individual effects
of each e.g. gentamycin + Ampicillin have synergistic effect in the
treatment of bacterial infections.
 Tolerance: - is the gradual decrease in response to a drug as a result of
repeated drug administration and the body adapts to the continued
presence of the drug. So it takes a higher dose of the drug to achieve the
same effect as when the person first use.
 Drug dependence: - this is the compulsive use of a substance resulting
in physical, psychological or social harm to the user with continued use
despite the harm.
 Allergic reaction:-this is an immunologically mediated adverse response
to a drug requiring previous sensitization. e.g. Rhinitis (nasal
congestion), itching, hives (urticarial)
 Anaphylaxis:- this is a state of immediate hypersensitivity following
sensitization to a foreign protein or a drug. It is characterized by itching,
swelling of the mouth, wheezing sudden drop in blood pressure and
sometimes death.
 Idiosyncrasy:- this is the production of unusual and unpredictable
pharmacological response to a drug based on genetic predisposition even
with the smallest dose .e.g. morphia is a central nervous depressant but in
some individuals produces CNS stimulation.
 Teratogen:- is any agent e.g drug that can induce or increase the
incidence of a congenital malformations/ birth defect. e.g. tetracycline
known to impair bone growth in in infants and staining primary or
deciduous teeth. Alcohol causing intra-uterine growth retardation (IUGR)
 Carcinogenic:- is any agent that induces cancer growth. E.g. tobacco
PRINCIPLES OF PHARMACOLOGY
Pharmacology is divided into two:-
 Pharmacokinetics
 Pharmacodynamics

1. PHARMACOKINETICS
Pharmacokinetics is the study of what the body does to the drug. It
includes:-
 Absorption
 Distribution
 Metabolism
 Excretion
A. DRUG ABSORPTION.
Absorption is the movement of a drug from one site of administration into
the blood stream (general circulation).drugs are absorbed from the
gastrointestinal tract mainly by passive diffusion or active transport.
Therefore, before a drug can exert a pharmacological effect in tissues, it
has to be taken in to the blood stream.
Factors that affects absorption.
 Route of administration
Oral Drugs take the longest time to be absorbed while injected
medications are usually absorbed more rapidly. Drugs given
intravenously are placed directly into the vein and so not absorbed and
take effect quickly.
 Rate of dissolution of a drug.
Since a drug has to be dissolved before its absorbed, drugs present in
formulations that allows rapid dissolution will be absorbed faster.
 Blood flow.
Absorption of a drug is faster from sites where blood flow is high.
For example, patient in shock may not respond to (IM) administration of
drugs because of poor peripheral circulation
 Lipid solubility

Highly lipid soluble (lipophilic) drugs can readily cross the membrane
compared to those with low lipid solubility because cell membranes
have a fatty acid layer.
E.g. parenterally administered drugs prepared in oily vehicle will be
more slowly absorbed than drugs dissolved in water or isotonic
sodium chloride
 Ph.
Acidic drugs are well absorbed in the stomach (acidic membrane).
Drug that is basic remains ionized in acidic environment and so not
absorbed before reaching the small intestine.
Take Note….
1. Drugs that are acidic (e.g. Aspirin) become relatively
undissociated in an acidic environment such as the stomach.
And therefore can readily diffuse across the membrane into
the circulation. In contrast, a basic drug tends to ionize in the
stomach acid environment and not absorbed through the
gastric mucosa. The reverse occurs when the drugs are in an
alkaline media.
Therefore, a basic drug is well absorbed in a basic medium
while acidic drug is well absorbed in an acidic environment
2. The unionized drug is lipid soluble and readily diffuses across
the cell membrane, the ionized drug is lipid insoluble and
non-diffusible
 Nature of the absorbing surface (cell membrane), through which
the drug must traverse.
The drug molecule may pass through a single layer of cells (intestinal
epithelium) faster than several layers of cells (skin).

 Drug concentration: - Drug administered in high concentration tend
to be more rapidly absorbed than drugs administered in low
concentration.
BIOAVAILABILITY.
(Bioavailability is sometimes confused with drug absorption). Therefore
bioavailability is defined as;-
This is the extent to and the rate at which moiety (drug or metabolite)
enters systemic circulation in a chemically unchanged form thereby
accessing the site of action.
OR
The term bioavailability denote to the proportion of the administered
dose of the drug which reaches the circulation
For e.g. if 10mg of a drug is administered orally and 7mg of this drug
absorbed unchanged, the bioavailability is 0.7 or seventy percent-70%.
Graph showing the effect of the route of administration of a drug on
the plasma concentrations after a single dose.
Drug given intravenously
Drug given intramuscularly
Drug given orally
Time
Plasma
concent
ration
of the
drug

NOTE:-
Many drugs bind to serum protein (albumin) from which they released
gradually, others stored at specific site as bone (tetracycline). Drug isn’t
to be bioavailable if:
1- Bound to protein or to any other substance that makes the drug
permanently or temporarily inactive.
2- Not released from its dosage form or site of administration.
3- Partially or totally degraded.
FACTORS THAT AFFECT BIOAVAILABILITY.
 First pass metabolism:- (It is the phenomenon of drug metabolism
where the concentration of a drug is greatly reduced before it reaches
the systemic circulation)
When a drug is absorbed across the GI truck, it first enters the portal
circulation before entering the systemic circulation. If a drug is rapidly
metabolized on its first entry into the liver, the amount of unchanged
drug that reaches the system’s circulation is decreased. Notable drugs
that experience a significant first-pass effect
are imipramine, morphine, propranolol, , diazepam, midazolam, pethidin
e, cimetidine, lidocaine, and nitroglycerin.
Alternative routes of administration like;-
 suppository,
 intravenous,
 intramuscular,
 inhalational,
 transdermal and
 sublingua
Avoid the first-pass effect because they allow drugs to be absorbed
directly into the systemic circulation.
Figure 2: an example of first pass
metabolism of a drug

 Solubility of the drug:-drugs that are very highly hydrophilic are
poorly absorbed because of their inability to cross the lipid rich
cell membranes. Hence for a drug to be readily absorbed, it must
be largely hydrophobic yet have some solubility in aqueous
solutions
 Chemical stability:-some drugs such as penicillin G are unstable
to ph. gastric contents. Others such as insulin, are destroyed in the
GI tract by degradative enzymes.
 Nature of the drug formulation:-the size of the particles, salt
form and excipients such as binders, disintergrants can influence
the ease of the dissolution and affect the rate of absorption of the
drug.
(Disintergrants are agents added to tablet (and some encapsulated)
formulations to promote the breakup of the tablet (and capsule
“slugs’) into smaller fragments in an aqueous environment thereby
increasing the available surface area and promoting a more rapid
release of the drug substance.)
(Therefore; intravenous administration has 100% bioavailability)
(Learners should critically think with reasons which route follows
next)
B. DRUG DISTRIBUTION
Distribution is the movement of a drug from the general circulation
into different organs and fluids of the body.
Therefore,
1. Drug enters blood stream
2. Next may diffuse into the extracellular fluid.
3. Finally, enter cells
4. Some drugs fix onto the cell membrane or other structures.

Factors that influence the distribution of drugs.
 Blood flow to the tissues. The drug distribution to a particular
organ or tissue depends on the tissue perfusion rate (volume of the
blood that flows per unit time per unit volume of the tissue).
 Highly perfused tissues such as lungs, kidneys, liver, heart;
adrenals are rapidly equilibrated with lipid soluble drugs.
 Muscles and skin are moderately perfused so they equilibrate
slowly with the drug present in blood.
 Adipose tissues, bones and teeth being poorly perfused, take
longer time to get distributed with the same drug.
 Summary: - liver→ kidney → muscle.
 Disease states: distribution of several drugs (through Capillary
permeability) that is ability of a drug to exit the vascular system
are altered in disease states, e.g.
 In meningitis and encephalitis, the blood brain barrier
becomes more permeable and the polar antibiotics like
penicillin-G, which do not normally cross it gain access to
the brain.
 In congestive heart failure or shock the perfusion rate to the
entire body decreases, which affects distribution of drugs
 In hypoalbuminaemia, plasma protein binding of the drugs
may be reduced and high concentration of free drugs may be
attained.
 Cell membranes and barriers that keeps out some drugs from
certain tissues. (The ability of a drug to enter cells)
 these barriers are
 blood brain barrier,
 placental barrier,
 Other barriers are; the prostate, testicles, and globe of eyes.
Lipid soluble drugs can penetrate and reach these structures freely,
whereas water soluble drugs entry is restricted.

 Protein binding capacity The distribution phase can be extremely
slow for drugs that bind strongly to serum proteins, because the
drug- protein complex is unable to pass out of the plasma
 Regional ph.
Blood drug level is the amount of the drug circulating in the body. It
helps in monitoring the effectiveness and the toxic effects of the
drugs.
C. DRUG METABOLISM. (METABOLISM)
Definition.
Metabolism is the enzymatic alteration of a drug structure. This
normally takes place in the liver. Metabolism may result in the
following:-
 Promotion of renal excretion of the drug
 Activation of inactive drugs (pro-drugs)
 Enhancement of therapeutic action of the drug.
 Alteration of the toxicity of the drug.
Liver is the primary site of drug metabolism, but other tissues also
may be involved in this process as plasma, kidney, lungs, and the
intestinal mucosa.
The process occurs by:-
1- Conjugation reaction: union of the polar group of a drug with
another substance in the body. The conjugated molecule also
becomes more polar & more water soluble, therefore more
excretable.
2- Oxidation- reduction reaction:-
3- Hydrolysis
These responses generally produce a loss in pharmacological activity
and occasionally are referred as DETOXIFICATION reactions
Factors influencing individual drug metabolism rates
 Genetics
 Co-existing liver disorders e.g. chronic liver disorders.

D. EXCRETION.
Excretion is the removal of drugs from the body.
The major organs involved here are the;-lungs, kidney, and the skin
Drugs may be excreted from the body through any of the following
ways:-
-The routes of elimination are:
1. Kidney: The majority of drugs and/or their metabolites are
excreted through the urine.
2. Lung: The gases and volatile liquids, as general anesthetic, are
excreted across the lung in the expired air.
3. Intestine: Many agents are eliminated through the intestine in the
feces by biliary excretion.
4. Sweat and salivary glands (may cause skin rashes).
5. Mammary glands … Transfer from mother to baby.
N.B.:
Because of renal disease, the risk of drugs accumulation and drug
toxicity is increased. Note that dosage is reduced for most drugs in the
presence of impaired renal function ―some drugs can’t be given.
Onset

FACTORS THAT INFLUENCES DRUG ACTION
1. Tolerance; tolerance to a drug occurs when the body becomes overly
adapted to the drug and fails to respond to the drug at the cellular
level. Acquired tolerance occurs after taking a particular drug for an
extended period of time.
2. Timing; the time of day that the drug is taken may have impact on its
effect. Drugs affecting the body’s diurnal rhythms (day/night
processes) should be given at times to match the body’s natural
responses. E.g.to prevent specific side effects, for example stomach
irritating drugs are to be taken with meals, while hypnotics at bed
times
3. Size of the patient; -, the larger the body surface area, it will lower
the concentration of a given drug and it will produce less intense
action. E.g. an average dose of medication is given to a very tall or
very obese or very small and thin patient, the concentration of the
drug in the blood stream will not be the right amount to produce the
desired effect.
To correct the variation due to the different systems in weight, the
dose will be expressed in terms of dose per kg body weight of a
patient e.g. a patient weighing 80kg and a dose of 10mg/kg of a drug
is prescribed, the patient will receive dose 80 x 10 = 800 mg. greater
accuracy can be achieved using the dose relating to the surface area of
the patient e.g. from patient’s weight and height, the dose will be
expressed as dose per square meter of the body surface area.
4. Route; some drugs are incompletely absorbed after oral intake but
when given intravenously, their dose has to be reduced.
5. Age; - age may modify the way drugs are handled in the body and the
body will react to the action of the drug. : Pharmacokinetics of many
drugs change with age. –
 Newborn: liver and renal function less developed –

 Elderly: hepatic and renal functions decline –
 Glomerular filtration rate: low in infants –
 Blood brain barrier: more permeable in infants & may
cause accumulation
6. Disease condition; diseases can strongly affect how patients respond
to drugs; e.g. diseases of the liver and kidneys can affect how the
metabolism and excretion of drugs; congestive cardiac failure
affecting the distribution of drugs.
7. Concentration; - adequate dose is important to get therapeutic
concentration and how fast the body metabolizes and excrete the drug
depends on the physiochemical property of the drug.
8. Genetic factors; many drugs are broken down by enzymes which are
usually in the liver and it will terminate their actions there is
interpersonal differences in this activity of enzymes. The genetic
variation can exist with different metabolism of the drugs which is
known as genetic polymorphism (occurring in different form.
9. Race and drug response. Several ethnic groups may show different
sensitivity to some drugs. This could be due to differences in drug
metabolizing enzymes or differences in actual response to the drug.
10. Sex; women generally have a higher proportion of fat than men
hence react more strongly to certainly drugs than men.
11. Environmental factors; extremes of weather or temperature can
affect the action of some drugs e.g. heat relaxes the blood vessels and
speeds up circulation so drugs act faster. Cold slows their action by
constricting the blood vessels and slowing circulation. High altitude
makes some drugs ineffective because of the low oxygen levels.
12. Psychological factors; patients emotional status can result in
success or failure in therapy. E.g. negative emotions like jealousy,
anger, fear can lower drug effectiveness.

PHARMACODYNAMICS
Pharmacodynamics is the study of what the drug does to the
body
HOW DO DRUGS EXERT THEIR THERAPEAUTIC
EFFECTS?
A number of theories have been developed explaining different
ways by which drugs work; these include the following.
1. Drugs acting on enzymes: (drug-Enzymes interaction)
Enzymes are catalysts and carry out numerous reactions in the
body. A catalyst is involved in a reaction but remains unchanged at
the end of the reaction.
Enzymes react with substrate to create a product. If the product is
removed, more enzymes will combine with a substrate to form
more products. Enzymes are relatively or sometimes completely
specific for a certain substrate. There are two types of actions
known as competitive inhibition and non-competitive inhibition.
a) Competitive inhibition - the drug competes with the natural
substrate for the active Centre of the enzyme. Competitive
inhibition occurs when the enzyme combines reversibly with a
substance that has a very similar structure to the normal substrate
but because it is not normal, discards it and begins to look for
another substrate.

Drugs that act this way can be counteracted by increasing the
concentration of the substrate, and this is how many antidotes
work.
b) Non-competitive inhibition – The inhibitor (substrate) binds on to
a site distinct and remote from the active center of the enzyme
(Allosteric site). This causes a change in the structure of the
enzyme rendering it inactive. Non-competitive inhibitors combine
with the enzyme in a permanent and usually irreversible fashion.
Example Aspirin.

2. Drugs acting on receptors or (drug –receptor interaction):
The body cells contain certain structures called receptors these
combine with structures which are produced naturally in the body
and the cells are stimulated or inhibited, for e.g. the contraction of
muscles fibers produced by acetylcholine. The drug is brought to fit
into the receptor rather as a key fits a lock.
 A drug which binds to a receptor and produces a maximum effect
is called a full agonist.
 A drug which binds and produces less than a maximal effect is
called a partial agonist. Partial agonists produce an effect if no
agonist is present.
 Drugs which bind but do not activate a secondary messenger
system are called antagonists.
Antagonists can only produce effects by blocking access of the natural
transmitter (agonist) to the receptor. Ion channel blockers act on the ion
channel receptors associated with transporting ions (sodium,
potassium, calcium) to and from cells. Drugs react with the receptors in
channels to prevent the transport of ions. For drugs that are receptor
agonists -when a drug is administered the response usually increases in
proportion to the dose until the receptors are saturated.
Example: Olanzapine and Nifedipine
3. Drugs acting by physical action:
There are not many drugs which act in this fashion. One common
physical process occurring in the body is osmosis. Osmosis is
important in ensuring fluid balance between body compartments.
Osmosis results when two different concentrations of molecules are
separated by a semi-permeable membrane. Molecules can move from
areas of high concentration to low concentration. Some drugs can also
be largely adsorbent and bind to many materials in the body. This is
another type of physical action.

Example: Normal Saline 0.9% and Activated Charcoal
4. Action on cell membranes -Drugs acting by a physicochemical
reaction :( nonspecific interaction) i.e. no receptor or enzymes.
The function of the nerves and muscles depends on the ions passing
across membranes surrounding these cells.
Certain drugs interfere with the movement of these ions and thus
prevent nerve or muscle function as demonstrated by the mode of
action of anaesthetics.
Example: Anaesthesia
DRUG ADMINISTRATION
Course objectives
a) Define the terms (drug and drug administration)
b) List the principles/rules of drug administration
c) Define the commonly used abbreviations in drug administration
a) Definitions
Drug.
 A drug; Is any chemical substance which when administered
into a biological system causes physiological and
biochemical change in the body and intended for use in
diagnosis, cure, treatment and prevention of diseases.
OR
 Any chemical substance taken in the body or applied on the
surface for the diagnosis, cure, treatment, and prevention of
diseases.
Definition of Drug administration;

Drug administration is defined as the preparation, application and
evaluation of the effectiveness of a prescription and non-prescription
drugs.
b) PRINCIPLES/RULES OF DRUG ADMINISTRATION
1. Drugs are given only on written order by prescriber.
2. The prescription must be read carefully and then checked with the
medication label on the bottle.
3. Read the label on the bottle at least three times i.e.
 When the bottle is removed from the shelf.
 Before removing the medicine from the bottle/container.
 When returning the bottle to the shelf.
4. Ten (10) rights are observed.
I. Right patient
II. Right dosage
III. Right time
IV. Right
formulation.
V. Right site
VI. Right drug
VII. Right route
VIII. Right storage.
IX. Right disposal
X. Right equipment.
5. Verbal orders should be signed by the prescriber within the
specified period i.e. 24 hours in hospital and 48 hours in long term
care facilities.
6. The drug must always be identified by the label but never by the
colour of the label or supposed place on the shelf.
7. Never give a drug from unlabeled/ unmarked container or from
unreadable label.
8. Discard any unused dose of the medicine and never return it to the
bottle.
9. Never give medication by mouth to a patient who cannot swallow.
10. Give medications in time and report any omissions.
11. If a mistake is made report this immediately so that an
antidote can be given if necessary.
12. For children, crush the tablet, add water and if bitter, add
sugar.

13. Always keep in mind the patient’s rights regarding drugs i.e.
the right to know why he is getting the drug and the drug’s
undesired effects and patients have a right to refuse a drug.
14. Never give medications prepared by someone else.
15. Never allow your medication trolley/tray out of your sight.
This practice prevents any one from rearranging or removing some
of your medications without your knowledge.
ROUTES IN DRUG ADMINISTRATION
Definition of route of administration
A route of administration is the path by which a drug, poison or
other substances is brought into contact with the body.
There are various ways in which drugs are administered in to the
body. Drugs can be administered by several different routes as
determined by the intended site of action, rapidity and duration of
effect desired, chemical and physical properties of the drug.
 Parenteral route
 Topical route
 Enteral route
Factors to consider when choosing the routes of drug
administration
1. Site of action; must be correlated with the site of action.
For e.g. treatment of skin lesion by topical application.
2. Drug nature; drugs which are water soluble (hydrophilic
drugs) are to be injected intravenously because of its
difficulty to cross the cell membrane.
3. Onset of action; drugs injected/infused directly into
bloodstream are carried immediately throughout the body
or tablets placed under the tongue or between the cheek
and gums work quickly.

4. Duration of action; drugs intended for longer duration of
action are given by route where absorption is slow. E.g.
intradermal.
(Duration is the length of time a drug gives the desired response
or is at the therapeutic level)
5. Patient status; whether he is conscious or unconscious
6. Ease of administration; some patients are unable to
swallow e.g. very young or older adults
7. Desire of the patient.
1. PARENTERAL ROUTE.
The word parenteral means outside the intestines or alimentary canal
Several methods to administer a medication by parenteral route
involves injecting the medication into those tissues outside of the
intestines or alimentary canal and into the circulatory system.
Drugs given by this route are in form of solutions, suspensions, and
emulsions.
Parenteral route is the fastest route in which a drug can be absorbed.
It includes:-
 Intravenous (into a vein)
 Intramuscular (into a muscle)
 Subcutaneous/hypodermic
(into the subcutaneous tissue of
the skin)
 Intra-osseous (into the bone)
 Intracardiac (into the heart
muscles)
 Intraperitoneal (into the
peritoneal cavity)
 Intra-arterial (into an artery)
 Intradermal (into the dermis of
the skin
 Intrathecal (into the
subarachnoid space)
 Intra-articular (into the joints)

Figure 3 parts of the syringe
Figure 4 parts of the needle
EQUIPMENT
SYRINGES AND NEEDLES
 Needles are available in various lengths and gauges, with different
sizes of bevels.
 The needle length used depends on the route of administration.
 The gauge refers to the diameter of the needle.
 Needle gauges are numbered 18 to 30. As the diameter of the needle
increases, the gauge number decreases. For e.g. an 18-gauge needle is
larger in diameter than a 30-gauge needle
 Syringes are supplied in different sizes. Most syringes are plastic and
disposable.

obinabrahamolakaa1@gmail.com Page 34
CRITERIA OR FACTORS TO CONSIDER WHEN CHOOSING THE
TYPE OF THE SYRINGE.
1. Route of administration; a longer needle is required for an intramuscular
injection than for an intradermal or a subcutaneous injection.
2. Viscosity of the solution; some medications are more viscous than others
and require a larger-lumen needle to inject the drug.
3. Quantity to be administered; the larger the amount of the medication to
be injected, the greater the capacity of the syringe.
4. Body size; an obese person requires a longer needle to reach the muscle
tissue than a thin person. A thin person or an older adult with decreased
muscle mass require a shorter needle.
5. Type of medication; there are special syringes for special uses. E.g.
insulin syringe used to inject insulin.
Remember
 Do no recap used needles.
 After use place the needles and syringes in a puncture resistant
containers without being recapped because most needle stick injuries
occurs during recapping. If recapping is absolutely unavoidable, use
the one handed technique or the scooping method.
 The parts of the syringe/needles that must be kept sterile during drug
the procedure of preparation and administration of an injection include;
 The inside of the barrel
 The tip of the barrel
 Part of the plunger that enters the barrel (plunger/ piston)
 And the needle
a) Intravenous (IV) injection.
 This is when a drug is injected/administered directly into the blood stream
via a vein where it is distributed in blood all over the body
 It is administered at 15-20 degree angle.

 The injection of the vein should be with the direction of blood but not
against it.
Advantages Disadvantages
A quick onset of action is achieved Needs a trained personnel to
administer
The entire dose of the drug is
administered
In cases of toxicity retrieval of the
drug is not possible
A lower dose is given compared to
the oral route
It requires strict sterility
Administration is useful for drugs
that are irritant when administered
It is painful
Sites commonly used for intravenous injection
 The basalic and cephalic veins
 The accessory cephalic or the median ante-brachial vein
 The dorsal metacarpal veins
 The saphenous and femoral veins.
Hazard associated with intravenous injections
 Necrosis occurs if the drug is injected into the surrounding tissues
 Damage the arteries if the drug is injected accidentally into the arteries
 If the drug is given rapidly without following the doctor’s instructions,
undesired effects may occur.
 Sclerosis occurs if the veins are used frequently.
Points to remember
 The thinner the skin, the easier it becomes to locate the vein.
 Start choosing a site which is distal to the heart and more proximal
only when you fail to get a good vein.
 Select the size of the needle which corresponds to the vein.
 Avoid choosing damaged veins.
 For right handed patients, select veins of the left first and vice versa.
b) Intramuscular (IM) injection
Is an introduction of the drug in to the body’s system via the muscles
The drug is injected deep into one of the large skeletal muscular tissue e.g.
deltoid at an angel of 90º to the skin.

Purpose:
 To obtain quick action next to the intravenous route.
 To avoid an irritation from the drug if given through other route.
NOTE:
1. The needle for I.M should be long
2. Strict a septic technique should be observed throughout the
procedure.
3. Injection should not be given in areas such as inflamed, edematous,
those containing moles and pus
Drugs that give depot effect such
as benzathine penicillin can be
given by this route
It requires a trained personnel to
administer the drug
It is generally faster than
subcutaneous route
Absorption is sometimes variable
depending on which muscle is used
Relatively irritating substances
may be given.
Some drugs given IM may be
painful e.g. ceftriaxone injection.
It’s less painful compared to Iv
injection
Self-administration of the drug is
not possible
Muscles can tolerate bigger
volumes of the drug
Safest Sites for intramuscular injections
1. The gluteal muscle
 This is the safest site. The sciatic nerve runs beneath the inner and
lower parts of the buttocks, and so great care must be taken to avoid
piercing it.
2. The thigh muscles
 The upper outer third of the muscles of the thigh.
Injections in this area are often painful especially for those who have to walk
and this site should only be used by a trained nurse.
Up to 3 mls of medication may be administered
3. The deltoid muscle
 Muscles of the shoulder may be used for small injections up to 2mls if
the patient has enough muscle, but this site is best avoided.

Z-TRACT TECHNIQUE
 The Z-track method is a type of IM injection technique used to
prevent tracking(leakage) of the medication into the subcutaneous tissue
(underneath the skin). During the procedure, skin and tissue are pulled
and held firmly while a long needle is inserted into the muscle.
 Z-tract technique is used for injecting medications that are irritating to the
tissues Z-tract IM injection seals medication deep within the muscle tissue
 It doesn’t allow medication to leak into the subcutaneous tissues as the
needle is withdrawn.
Likely complications associated with I.M injection
 Abscess formation
 Nerve injury
 Cysts and necrosis
 Injecting the drug into a blood vessels
 Needle may break.
c) INTRADERMAL INJECTION;
Definition: It is an injection given into the dermal layer of the skin
(corneum)
Can accommodate upto 1Ml of drug
Purpose
 For diagnostic purpose

a. Fine test (mantoux test) (tuberculin test)
b. Allergic reaction (skin sensitivity test because of the slow
absorption rate)
 For therapeutic purpose
c. Intradermal injection may also be given like in vaccination
Site of Injection;
 The inner part of the forearm (midway between the wrist and elbow.
 Upper arm, at deltoid area for BCG vaccination
d) Subcutaneous (SC)/hypodermic injection.
The drug is injected in to the subcutaneous tissues, the fatty layer of the tissue
underneath the dermis. It is commonly used in administering vaccines,
heparin and insulin. This route of administration like the intramuscular;
provides absorption that is slower than the IV route
Up to 2mls of drug can be administered at 45º and takes about 15-20 minutes of
the drug to be absorbed.
Note.
If repeated injections are given, the nurse should rotate the site of injection so
that each succeeding injection is about 5 cm away from the previous one.
Absorption is slower than IM
injection complete
Can be painful
possible
Irritating drugs may result in
severe pain and local tissue
necrosis
Care must be taken not to inject iv
Suitable sites
Outer aspects of the upper arm.
 Anterior and lateral aspects of the thigh
 Upper back.

 Any other sites where there is no bonny prominence and where it is
free from blood vessels and nerves
The sites should be rotated to make sure that injections are not given in
the same site.
Intra-arterial injection
 This route is used by doctors to introduce a drug directly into an artery in
some forms of carcinoma. Pressure is needed to inject the drug.
Intra-articular
 This is an injection given into the joints.
Intra-thecal injection.
 After lumber puncture has been performed, drugs may be given into the
cerebral spinal fluid and this site is used.
Intra-osseous
 Intra-osseous is to get access into the general circulation via the bone
marrow.
 It is recommended for emergency administration of fluids and drugs in
infants and children.
Sites recommended
 The tibia, the femur, and the iliac crest.
 This procedure is performed by a doctor and it is a sterile
procedure.
GENERAL ADVANTAGES OF PARENTERAL ROUTE
 The drug acts quicker than the oral route, for this reason, it is very
useful in emergencies.
 It is the route of choice when the patient is unconscious or when there
is nausea and vomiting.
 The route is very useful for uncooperative patients who refuse to take
the drug orally. (E.g. some psychiatric patients).

 For drugs which are not absorbed by gastrointestinal tract or are made
inactive by digestive juices, the parenteral route may be the only choice
e.g. insulin.
 The desired dose can be determined more accurately.
 Some patients gets psychological satisfaction with injections.
 Small doses of powerful drugs can be administered more efficiently.
Disadvantages
 Syringes and needles which are needed for this technique are
expensive.
 Injections are painful to some patients esp. children may be tense prior
to and injection.
 An abscess may occur at the site of an injection especially if sterility is
not maintained during the procedure.
 Drugs given by this means may be difficult to neutralize if any
undesirable effect occurs.
 If injection site is not carefully selected, nerves may be injured
resulting into paralysis.
 Air embolism may occur especially if air is not completely expelled
from the syringe before giving an injection.
 Irreversible effect may occur if an overdose is given.
2. TOPICAL ROUTE
Drugs are applied directly on the skin or mucus membranes of the eye, ear,
nose, lungs, vagina or urethra. Drugs given by this route are in form of
creams, ointments, lotion, gels sprays etc.
possible
Some drugs like dithranol stain the
skin and clothe
Its less expensive compared to
parenteral route
Adverse skin reactions are possible
It’s easy to monitor the treatment Some drugs like topical steroids
bleach and cause thinning of the
skin

Wastage of the drug is possible
since there is no measurable dose
3. ENTERAL ROUTE
Entero- of intestine
This includes rectal, oral, sublingual, and buccal routes.
A. Rectal route.
Drugs are administered via the rectum inform of suppositories or enema.
Purpose;
 To produce a laxative effect. (Bowel movement), suppository is
used frequently instead of enema since it is inexpensive.
 To produce local sedative in the treatment of hemorrhoids or rectal
abscess.
 To produce general sedative effects when medications cannot be
taken by mouth
Provides a safe route for a
patient who is vomiting,
unconscious or un able to
swallow
May be uncomfortable and
embarrassing for a patient.
Provides an effective route to
treat vomiting
Drugs may results in irregular or
incomplete drug absorption
depending on whether faeces are
present
No sterilization required
It is faster than oral route May stimulate the patients vagal
nerve by stretching the anal
sphincters
It avoids destruction of the
medication by digestive

enzymes In stomach and small
intestine.
Drugs may be given for local
effects e.g. haemorrhoids
B. Oral route
Oral medication is drug administered by mouth
The oral route is the most convenient and the safest route of drug
administration. Drugs are given by oral route in form of tablets, capsules,
syrups, suspension, or powders.
Purpose
a. When local effects on GI tract are desired
b. When prolonged systemic action is desired
It is cheap for the patient Has a delayed function and hence
no suitable for emergencies
It does not require a skilled
personnel to administer the drug
It requires patience commitment to
improve on compliance
possible
Oral route cannot be used by a
patient in coma
Some drugs can only be given by
oral route e.g. Nifedipine
Psychiatric patients and children
may refuse to take the drug by oral
route
In case of drug toxicity, it can be
retrieved
Some drugs can be destroyed by
the GIT enzymes e.g. insulin
It is not suitable for a patient who
is vomiting.
A higher dose is required
compared to parenteral route.
C. Sublingual route

The drug usually in form of a tablet is placed under the tongue and
allowed to dissolve slowly e.g. nitroglycerin.
The drug is absorbed quickly through the oral mucus membrane in to the
blood stream. It provides faster therapeutic response than the oral route.
COMMON ABBREVIATION USED IN DRUG
ADMINISTRATION
Abbreviation Meaning.
Od Once daily
Bd or q12hrs Twice daily
Tds or q8hrs Three times daily
Qid or q6hrs Four times daily
q.h Every hour
p.r.n Whenever needed
Stat Immediately
o.m Each morning
o.n (noct Each night
a.c Before meals
p.c After meals
p.o By mouth
i.m Intramuscular
i.v Intravenous
Sc Subcutaneous
Mist Mixture
Inj Injections
Aq Water
Caps Capsules
Tab Tablet
Supp Suppository
Pess Pessary
Syr Syrup
Ung Ointment
Inf Infusion
Enem Enema
Gut Drops

G Gram
Mg Milligram
Ml Milliliter
µg Microgram
Pr Per rectum
Ss or fs Half
Sos If necessary
Pv Per vagina
INTERPRETATION OF PRESCRIPTION
(PRESCRIPTION WRITING)
By the end of this chapter, students should be able to;-
1. Define the term prescription
2. Differentiate between prescription and medication orders.
3. Identify the components of a prescription and medication order.
4. Interpret abbreviations that are commonly used in prescription and
medication orders
5. Interpret prescriptions and medications orders to determine how they need
to be prepared.
Definition;
Remember
Pre-before
Scription-written/or writing
This refers to the fact that the prescription is an order that must be written
down before a compound drug can be prepared
Prescription.

1. Is a written instruction from a prescriber (doctor, clinical officer, midwife, or
a nurse.) to a dispenser (pharmacist, pharmacy technician or nurse) on
medicines to be administered to a patient.
2. A written physician’s order for the preparation and administration of a drug
or advice for a patient
Prescriptions help to control the sale and effective use of drugs under the
supervision of a licensed health professional.
Who are the Persons licensed to prescribe.
This may vary from state to state according to the medical practice act of the
particular state. Usually the following persons are licensed to prescribe
 Dentists
 Medical officers
 Specialized medical officers like physicians, pediatricians, gynecologists
 Registered nurses like palliative care nurses.
Qualities of a good prescriber
A good prescriber;-
 Prescribe medications when necessary
 Choose treatment regimen that is appropriate to the patient’s disease
 Continues treatment for appropriate time and alters doses of therapy when
necessary
 Prescribes the right medication according to the patient’s diagnosis.
 Give a clear explanation to the patient about his or her condition.
 Explains the effect of the drug and why it’s needed.
 Give information about possible adverse effects of the drug and what to
do if they occur.
 Monitors the patients prognosis and advises the patient when to return for
review.
Definition of a dispenser
A dispenser is anyone who gives out the medicine/treatment to the patient or
client. Example; pharmacist, nurse or midwife.

Roles of a dispenser
 Dispenses drugs to patients and wards
 Gives drug information to the patient or client
 Keeps drugs records
 Ensures proper storage of drugs
 Advises the prescriber about drugs
TYPES OF PRESCRIPTIONS.
1. Prescription order
This is commonly used in the outpatient or ambulatory settings where the
patient may require entire dosages of the drugs to carry home.
2. Medication order
It’s an order that tells the health care worker which drug (s) to administer.
It’s not given to the patient to pick drugs from a pharmacy but is rather
used for the administration of drugs in hospitals and ambulatory facilities
(in patient).
Medication orders contain the following parts;-
 Date
 Patients name
 Medication name
 Dosage and amount of medication
 Route of administration
 Time and frequency of medication
 Signature of person ordering medication
COMPONENTS OF A PRESCRIPTION
For a prescription to be considered valid it must consist of the following
components:-
 Patients information

 Date
 Symbol or superscription
 Inscription (medication prescribed)
 Signa (direction for the patient)
 Subscription (dispensing directions to pharmacist)
 Prescriber’s name and license number
Patient’s information
 The full first and last name with correct spellings
Full address of the patient are necessary on the prescription for identification
purposes.
 Names and address written illegibly
 Incorrect spelling of the patient’s name on a prescription label might
cause concern in the patient’s mind as to the correctness of the medication
 Patient’s weight and age or date of birth may also be included to ease the
calculation of the right dose by the dispenser.
Date
 Prescriptions are dated at the time they are written
 Allows the determination of the life of the prescription to validate refills.
 Promotes patient follow-up
 Continues continual patient supervision.
 Therefore, the date is important in establishing the medication record of
the patient.
Symbol or superscription
 The Rx symbol generally is understood to be a contraction of the
latin verb recipe, meaning “take through” or “you take”
 Some historians believe this symbol originated from the sign J piter,
employed by the ancients in requesting aid in healing from gods
whose protection may have been sought in medical context. Gradual
distortion through the years has led to this symbol currently used.
 Note. Letter J was slanted crossing R forming Rx
 Today, the symbol is representative of both prescription and
pharmacy itself

Medication prescribed or inscription
o This is the body or the principle part of the prescription order. It
contains the name and strength of the prescribed ingredients(drug)
o The strength of the drug is usually in mg or ml for topical
preparations the strength is indicated by the percentage of the
medication in the base
o E.g. Amoxicillin 250mg, digoxin 0.25mg, salicylic acid%
o The brand name or generic name of the drug may be written on the
prescription chat
o Prescription orders requiring the pharmacist to mix ingredients are
termed as compounded prescriptions. Prescriptions requiring
compounding contain the names and strength of each ingredient
required.
Directions for patient or signature (label/instructions/warning)
o It contains the prescribers direction for patient’s use of the
medication
o The word usually abbreviated “signa” or means “mark thou” the
directions in the signa commonly are written using abbreviated
forms of English or latin terms or a combination of each
o E.g. 1 cap tds x 5/7
1 tab o.d x 3/7
Apply nocte x 7/7
o The directions are to be written by on to the lable of the container of
dispensed medication
o It’s advisable for the dispenser to reinforce the directions to the
patient upon dispensing the medications since the patient may be
uncertain or confused as to the proper method of use.
o These directions frequently include the best time to take the
medications, the importance of adhering to the prescribed dosage
schedule, the permitted use of the medication with respect to food,
drink and other medications the patient may be taking as well as
information about the drug itself

Dispensing directions to pharmacists or subscription.
 This part of the prescription consists of directions to the pharmacist for
preparing the prescription.
 In a large majority of prescriptions, the subscription serves merely to
designate the dosage form (as capsules, tablets, etc.) and the number of
dosage units to be supplied.
 e.g. diclofenac gel apply prn( supply two)
Prescriber’s information
 The content of the prescription should include the name and address of
the prescriber and any other legal requirement such as a registration
number.
 The prescriber’s information helps the pharmacist or dispenser to
communicate with the prescriber in case of prescription errors or need for
clarification due to ineligible handwriting
Processing the prescription order (The dispensing process)
The process of dispensing is undertaken by the dispenser.
A dispenser is anyone who gives out the medicine/treatment to the patient or
client. He may be a pharmacist, Nurse, or a Midwife.
Roles of a dispenser
 Dispenses drugs to patients and wards
 Gives drug information to patients or client
 Keeps drug records
 Ensures proper storage of drugs
 Advises the prescriber about the drugs
 Sometimes procures drugs.

Example
RATIONAL USE OF MEDICINE
This is when patients receive medicines appropriate to their clinical needs, in
appropriate doses and for an adequate period of time at costs affordable to
them and community.
Irrational use of medicines;-
This involves
 Use of too many medicines per patient,
 Wrong choice, of drugs for a particular condition,
 Inadequate dosages and
 Unnecessary use of injections where oral dosage form can be
applicable,
 Indiscriminate use of antibiotics in the treatment of viral infections.
Factors underlying irrational medicine use;-
 Heavy patient load hence most prescribers target clearing the line
 Poor communication skills among the medical personnel.
 Inappropriate interpretation of laboratory results.

 Poor attitude towards work.
 Misleading beliefs by a patient where some more in injection than oral
drugs.
 Inconsistent drug supply in health centres.
 Lack of medicine formulary in hospitals.
 Misleading promotions by drug companies.
 Inadequate drug regulation
 Bribing of prescribers by drug companies.
 Poor attitudes towards continuing medical education (CME)
Consequences of irrational medicine use;-
 Over use of antibiotics leads to the development of resistance.
 Leads to wastage of scarce resources.
 Leads to increased cost of drugs to patients.
 Increases adverse drug reactions especially with polypharmacy.
 May lead to loss of patient’s confidence in the health system.
 May lead to poor patient’s outcome
CONCEPT OF ESSENTIAL DRUGS
By then of this topic, learners should be able to
1. Define essential drugs
2. Explain the criteria used in selection of essential drugs
3. Outline the importance of applying the concept of essential drugs.
Definition.
Essential drugs (medicine) are those that satisfy the priority health care
needs of the population; these drugs should therefore always be available
in adequate quantities and appropriate dosage forms with assured quality
and information and at a price the individual and the community can afford.
Criteria for selection of essential drugs;
 Pattern of disease prevalence in the community
 Availability of facilities for manufacture and storage.

 Training and experience of available personnel to handle, prescribe and
distribute/ dispense the drugs.
 Available financial resources by government to procure drugs so that
the community at the grass route level can afford to access them.
 Genetic, demographic and environmental factors
 Efficacy and safety proven from clinical data and able to produce
adequate therapeutic effects.
 Assured quality and bioavailability to meet the therapeutic demand.
 Stability under normal conditions of use and storage
 Cost effectiveness; a cost effective drug is one that produces the
greatest output in return for each unit of input
 Benefit /risk ratio- this depends on safety and efficacy data with
consideration of potential of misuse. This concept may be applied to a
single drug or in comparison to two or more drugs for the same
indication.
 Formulation as single compounds.
 Combination products evaluated on the basis of therapeutic effect
 Safety and patient compliance.
Advantages/Importance of applying Essential drug concept;
The concept of essential drugs is that limited number of carefully
selected drugs based on agreed clinical guidelines leads to the
following;
 More rational prescribing and therefore higher quality of care and
better value of money. (fewer drugs better therapy)
 Training of health workers and drug information can be more
focused.
 Prescribers gain more experience with fewer drugs and recognize
drug interactions and adverse reactions more easily.
 Quality assurance, procurement, storage, distribution and
dispensing are easier with reduced number of drugs

 The procurement of fewer items in larger quantities results in
more price competition and hence, lower costs.
DOSE AND DOSAGE CALCULATION
OBJECTIVES
By the end of this lecture learners should be able to:-
1. Differentiate between dose and dosage.
2. Identify human errors that can happen during a drug therapy?
3. Calculate various drug doses?
4. Calculate intravenous flow rate i.e. drop per minute or drop per hour
5. Convert different metric units.
Definitions.
Dose
 The amount of a drug to be administered to a patient at a time to obtain a
desired pharmacological effect.
Dosage
 It is the determination of the amount, route, frequency and number of
doses of medication for a patient. It should include
 The formulation of the drug
 Name of the drug
 Amount of the drug
Types of medication errors
Definition;- Medication errors, broadly defined as any error in the
prescribing, dispensing, or administration of a drug irrespective of
whether such errors leads to adverse consequences or not, and are the
single most preventable cause of patients harm
 Wrong dose
 Wrong patient
 Wrong route

 Patient allergic to
treatment
 Contraindicated
 Wrong/omitted/passed
expiry date.
 Wrong label
 Wrong storage
 Wrong formulation
 Wrong frequency
Overview
 Abbreviations
 Metric conversions
 Desired dose
 Concentrations
 Drip rates
Abbreviations
 Cc-cubic centimeter
 DD- Desired Dose
 Gm-gram
 Gtt- drop/drops
 IM- Intramuscular
 IO-Intraosseous
 IV-Intravenous
 Kg-Kilogram
 L-Liter
 Mcg-microgram
 mEq-lilliequivalant
 mg-milligram
 µg-microgram
 µgtt-micro drop
 D5NS-5% dextrose in
0.9% sodium chloride
 Cl- Chloride
 Na-Sodium
 K-Potassium
 So4-Sulphate
 Mmol-millimole
Metric conversion
 Kg , g , mcg
 Lbs. to Kg
 L to ml

Kg , g , mg , mcg
o To convert if going from large value to smaller value, move the
decimal point 3 places to the right for each conversion.
o If going from smaller value to larger value, move the decimal
point to the left for each conversion
 3.0 Kg =3,000g
 3.0 Kg mg =3,000, 000mg
 3.0 Kg =3,000,000,000mcg
L to ml
 1L =1,000ml
 500ml =5L
(I.e. L to mL you multiply by 1000 while mL to L you divide by
1000)
Convert to mg
 300 mcg =0.3mg
 6Kg =6,000,000mg
 450g =450,000mg
 42Kg =420,000mg
 14g =14,000mg
 1000mcg =1mg
ML vs. cc
A mL and a cc have the same value. Therefore;
 1mL= 1 cc
 500mL=500 cc
 0.5 cc= 0.5Ml
DESIRED DOSE
The amount of a particular medication to be administered.

The symbol “/” stands for per
Example.
 A patient with chest pains needs to be given 4mg of
morphine sulphate for chest pain.4mg is the desired dose
 A paediatric patient is to receive atropine 0.02mg/kg. the
patient is 18kg. what is the desired dose DD? 0.36mg is the
DD.
CONCENTRATION
 The concentration is found by dividing the weight by the
volume.(e.g. 50mg/2mL). The answer will result in the
concentration/mL of the medication
e.g.
 diclofenac is ordered 50mg. it is supplied 75mg/3mL. what is
the concentration? It is 25mg/Ml
CALCULATING THE ML TO BE GIVEN
There is a very simple mathematical equation to calculate the mL to
be given
(D/H)*Q
 Dose you want to give (mg/mcg)
 What do you Have it supplied in (mg/mcg)
 What Quantity dose it come in (mL)
OR
Volume required =
strength required
stock strenth
∗ volume of stock
Example... 1.
You can think of
𝒔𝒖𝒏𝒓𝒊𝒔𝒆 𝑺𝑹
𝒔𝒖𝒏𝒔𝒆𝒕 𝑺𝑺
To remember this
formula

o A patient is ordered 70 mg of pethidine. Find the volume required
if the stock solution contains 10 g of pethidine per 200 ml.
To solve; note down the strength of medication (or the desired
dose) the patient needs and the stock strength
 Strength required is 70 mg, stock strength is 10 g in 200mL.
 since you need units to be the same, convert 10 g to mg by
multiplying by 1000:10 g =10*1000 = 10,000 mg
Note. g to mg you multiply by 1000 while mg to g you divide by
1000
Volume required =
strength required
stock strenth
∗ volume of stock
Volume required =
70 𝑚𝑔
10,000 𝑚𝑔
∗ 200 𝑚𝐿
=
14000
10,000
mL = 1.4mL of pethidine
Notice that 70 mg (what the patient needs is a very small part of this
10,000 mg so expect your answer to be much smaller than 200 mL
Example 2.
A vial of a drug contains 40mg/2ml.
How many milliliters (ml) are required to obtain 300mg of drug?
4𝑚𝑔
2 𝑚𝐿
=
300 𝑚𝑔
𝑥
(40mg)(x)=(2ml)(300ml)
X=
(2 𝑚𝐿)(300 𝑚𝑔)
(40 𝑚𝑔)
x= 15ml

Example. 3. Tablets taken orally
This example illustrates how many tablets to give for a certain dose.
750 mg of ciprofloxacin is prescribed. On hand are 500 mg tablets.
How many tablets should be given?
Strength required is 750 mg
Stock strength is 500 mg
From Volume required =
strength required
stock strenth
∗ volume of stock
Volume required =
750 𝑚𝑔
500 𝑚𝑔
∗ 1 𝑡𝑎𝑏𝑙𝑒𝑡= 1.5 tablets i.e. one and half
tablets
Note; when administering tablets, the volume of stock is always
one, since the tablets are not supplied in solutions
TRIALS
o Lidocaine is ordered 1mg/kg to a patient that weighs 68.2 kg. It’s
supplied in 100 mg/5 mL. How many mL will you need to give?
o The answer is 3.4mL
o Lasix is ordered 40mg IVP. It is supplied 100mg/3mL. How many
mL will you need to give?. The answer is1.2mL
o Epinephrine, 3mg SQ is ordered to a patient with anaphylaxis. It is
supplied 1mg/mL. How many mL will you need to give? The
answer is 3mL.

DRIP RATES
Calculation of Intravenous Drip Rates
In these types of calculations, for a given volume, time period, and
drop factor (gtts/mL), the required IV flow rate in drops per minute
(gtts/min) is calculated. Note: Since a fraction of a drop is not
possible to give to a patient, it is usual to round the answers to the
nearest whole number.
formula:
OR
Example 1: Calculate the IV flow rate for 250 mL of 0.5% dextrose
to be administered over 180 minutes. The infusion set has drop factor
of 30 gtts/mL.
Steps 1 determine your givens: volume: 250 mL and time: 180 min,
drop factor: 30 gtts/mL
Step 2use the formula to calculate the IV flow rate. Remember to
round the final answer to the nearest whole number.
𝑣𝑜𝑙𝑢𝑚𝑒 (𝑚𝐿)
𝑡𝑖𝑚𝑒 (min)
X drop factor gtts/mL = Y (gtts/min)
250 𝑚𝐿
180 𝑚𝑖𝑛
𝑋30
𝑔𝑡𝑡𝑠
𝑚𝐿
= 41.66
𝑔𝑡𝑡𝑠
𝑚𝑖𝑛
Volume(mL) * Drop factor (gtts/mL) =Y (flow rate in gtts/min
Time(min)

Therefore, the IV flow rate is 42 gtts/min.
Example 2: The infusion set is adjusted for a drop factor of 15
gtts/mL. Calculate the IV flow rate if 1500 mL IV saline is ordered
to be infused over 12 hours.
Step 1: Determine your givens. Volume: 1500 mL , Time: 12 hours ,
Drop factor: 15 gtts/mL
Step 2: Convert 8 hours into minutes. 12 h x 60 min/h = 720 min
Step 3: Use the formula to calculate the IV flow rate (gtts/min).
𝑣𝑜𝑙𝑢𝑚𝑒 (𝑚𝐿)
𝑡𝑖𝑚𝑒 (min)
X drop factor gtts/mL = Y (gtts/min)
1500 𝑚𝑙
720 𝑚𝑖𝑛
𝑋15
𝑔𝑡𝑡𝑠
𝑚𝐿
= 31.25𝑔𝑡𝑡𝑠/𝑚𝑖𝑛
Therefore, the IV flow rate is 31 gtts/min.
MEDICATION ADHERENCE/COMPLIANCE
How is adherence defined?
WHO definition:
‘the extent to which a person’s behaviour (i.e. taking medication,
following a diet and/or executing lifestyle changes ) corresponds
with agreed recommendations from a healthcare provider’
How are medication adherence and compliance different?

 Medication adherence is the act of filling new prescriptions or
refilling prescription on time.
 Medication compliance is the act of taking medication on schedule
or taking medication as prescribed
Non-adherence includes:
 Taking a dose at the wrong time
 Failed to fill a prescription
 Failed to refill a prescription
 Missed a dose
 Took a lower dose than prescribed
 Took a higher dose than prescribed
 Stopped a prescription early
 Took an old medication for a new problem without consulting a
doctor
 Took someone else's medicine
 Forgot whether they'd taken a medication
 Not attending clinic appointments.
 Not observing the dietary instructions
It has been suggested that increasing the effectiveness of
adherence interventions may have a far greater impact on the
health of the population than any improvement in specific
medical treatments
CAUSES OF NON-ADHERENCE
The challenge of non-adherence is multifaceted, with patients facing
barriers to adherence as a result to both supply and demand- side factors.
Circumstances that negatively affects adherence in care vary between
individuals and cross populations;

a) Patient-related barriers to adherence.
 Lack of knowledge and understanding about diseases and
treatments.
 Perception and beliefs in relation to disease management
 Affective factors (depression, anxiety, shame, etc.)
 Behavioral factors (e.g. missed appointments)
 Factors related to treatment burden and adverse drug event (side
effects)
 Socio-economic and demographic factors (disease related stigma,
transport, age, etc.
 Lack of support (e.g. social support)
b) Health system related barriers can include;
 Poor quality interventions (lack of health education, assessment,
communication, tracing systems, etc.)
 Lack of appropriate health care providers with skills and attitude.
 Inadequate training of staff in breaking bad news, educating and
supporting patients in adherence (delivery of test results and
explanation of significance.
a) Organizational barriers
 Long waiting time,
 Distance to the clinic.,
 lack of integration and of coordination between services
 medicine shortages and lack of stock
 Inflexible clinic hours.
 Lack of confidentiality
 Lack of tools to guide the health care workers on ways to
support patients’ adherence.
 Poor tracing system.

b) Medication-related factors
 Long length of treatment
 Complexity of treatment
 Unwanted side effects
 Cost of medicines
WHAT ARE THE CONSEQUENCES?
a) Patient consequences
 sub-optimal management of their condition
 potential harm resulting from sub-optimal management
 Reemergence of opportunistic infections in HIV patients,
diseases such as tuberculosis.
 increased disease progression and complications
 decreased quality of life
 increased patient morbidity and mortality rate
 This represents a failure to translate the technological benefits
of new medicines into health gain for individuals
b) Organisation consequences
 increased spending to counter sub-optimal patient
management
 sometimes increased clinical risk due to additional
prescribing
 increased cost of medicines dispensed but not used
 Higher hospitalization rates
 increased cost of safe disposal of unwanted medicines
SOLUTIONS TO NONCOMPLIANCE
1. Simplifying the Medication Regimen
The simpler the regimen is, the higher the rate of compliance is.

(eg, once-a-day dosing) should be considered to ensure that the
patient will adhere to the treatment plan.
2. Educating the Patient About the Disease
Patients need to be properly educated in a clear and concise way
about their disease states and the need for treatment. Even when
they feel generally feel fine.
3.Explaining Potential Side Effects and What to Expect
Pharmacists should discuss with patients not only the potential side
effects associated with a drug, but the importance of consulting
with their physician if an adverse effect becomes intolerable, so
that an alternative drug may be substituted.
Points to cover with patients to improve compliance include the
following:
a) How the medication works
b) How the medication is dosed
c) Major adverse effects
d) What to do in the event of an adverse effect
e) How the treatment will be followed or monitored
4. Improve communication between healthcare professionals and the
patients hence providing adequate information to patient and helping
them address their the concerns
5. Prescription collection strategies;-
 Adherence clubs like community adherence (ART) group
(CAG)
 Spaced appointments system.
 Decentralized medication delivery.
6. Training of health workers on the latest programme guidelines and
strategies.
7. Development of supervision and monitoring tools.
8. Encouraging the Use of Patient Reminder Aids

For instance, patients can integrate taking their medication into their
daily routine of getting up, brushing teeth, eating. Patients also may
place colored stickers on a calendar once they have taken a pill.
Some patients do well with a pillbox with a compartment for each day
of the week. Other memory devices include inexpensive wristwatches
with alarms and pill bottles with alarms in the cap that record the exact
time the bottle was last opened. Electronic vial tops also are available
that provide signals corresponding to a dosing schedule. If the cap is
not removed on schedule, the device will beep and flash.
CLASSIFICATION OF DRUGS
Drugs may be classified in the following ways:-
 Prescription classification
 Pharmacological classification
 According to drug legislation
1. Prescription classification
In this classification, drugs are classified basing on whether they are
obtained using a prescription (prescription only medicine) or they
can be obtained without a prescription (over the counter drugs)
 Prescription drugs;- these drugs can only be obtained when a
patient presents a valid prescription to a pharmacy. Examples of
prescription drugs includes:-Amoxicillin, ciprofloxacin, diclofenac
and Nifedipine among others.
 Non prescription drugs ;-( over the counter drugs). These drugs can
be obtained from either a pharmacy or a drug shop without a
prescription and include Panadol®, Hedex®,, vitamins and good
morning syrup®, among others.
2. Pharmacological classification.
 Pharmacological or therapeutic effect.
 Systems they target.

 Causative organisms they act against
 Mechanism of action
 Chemical structure of the parent compound
 Pharmacological or therapeutic effect.
This group of drugs looks at the effect on the body brought
about by the drug administered. Examples;-
 diuretics to relieve
oedema
 analgesics used to
alleviate pain
 anti hypertensives- to
lower high blood pressure
to nearly normal or
normal.
 antimalarials
 antihistamines
 antidiabetics
 antiepileptic
 laxatives
 antimicrobials
 anticoagulants
 antiarrythmics
 Systems they target.
This group looks at the body system that a particular medicine affects.
E.g.
 Cardiovascular system
medicines
 Respiratory system
medicines
 Genitourinary system
 Gastrointestinal system
medicines
 Reproductive system
medicine
 Central nervous system
medicines
 According to the causative organisms they act against;-
Examples.
 Antibacterial
 Antivirals
 Antifungal
 Antihelmintics
 Antiparasitics
 Mechanism of action;-
This group emphasizes the action of the drug at cellular level

Examples:-
 Calcium channel
blockers e.g. Nifedipine.
 Proton pump inhibitors
e.g. Omeprazole
 Beta blockers e.g.
propanolol
 Angiotensin receptor
blocker. E.g. Captopril
 Nucleoside reverse
transcriptase inhibitors
e.g. lamivudine,
zidovudine
Note that there may be many drugs targeting the same condition ( e.g.
hypertension) but each act in a different way
 Chemical structure of the parent compound;-
Many drugs sharing the same structure generally have
o Similar indications (pattern of activity)
o Effectiveness
o Toxicity
o Same side effects and contraindications.
Unfortunately, classifying drugs according to their chemical structure
type has the disadvantage that members of the same structural
group often exhibit very different types of pharmacological
activity.
For example;- steroids, may act as hormones(testosterone),
diuretic(spironolactone), antibacterial agents(fusidic acid) amongs
other forms of activity.
3. Legal classification.
This divides the drugs into three as follows basing on the potential of
abuse and addiction
 Class A

These are the Narcotic group of drugs and were previously under the
Dangerous Drug Act (DDA) and are of high potential of being
abused. These include the following
 Morphine
 Diamorphine
 Pethidine
 Cocaine
 Methadone
 Dihydrocodeine
 Class B
 All antibiotics
 All sulphonamides
 All barbiturates
 All diuretics
 All anesthetics
 All eyes and nasal drops
 All vaccines
 All preparation for whole human blood
 Class c
Are also called Over the counter (OTC). drugs including
o analgesics like acetaminophen (paracetamol), ibuprofen
o vitamins like ferrous sulphate
o laxatives like bisacodyl
o anti antifungal creams and ointments like ketoconazole,
clotrimazole, nystatin

GENERAL REVISION QUESTIONS FOR STUDENTS
SECTION A --MULTIPLE CHOICE QUESTIONS
1. The study of drugs and their interaction with the living system is termed as…..
a. Pharmacology
b. Pharmacognosy
c. Pharmacogensis
d. Pharmakinetics
2. Drug name approved by a recognized competent drug body and is commonly
used in prescription is..
a. Chemical name
b. Non-proprietary name
c. Proprietary name
d. None of the above
3. ____________ is the ability of a drug to produce a maximal therapeutic
response
a. Potency
b. Efficacy
c. Affinity
d. Half life
4. Therapeutic index is
a. the ratio of the drug that produces the toxicity to those which produces
clinical response
b. The ratio of the drug that produces clinical response to those which
produces the toxicity.
c. The time taken to reduce the amount of the drug in the body by one half
during elimination.
d. is the dose between the minimum effective and the maximum doses
5. a substance that binds to a receptor and prevents a response is called
a. agonist
b. antagonist
c. partial agonist
d. Full agonist.
6. Which of the following is not a solid form of drugs
a. cream
b. pessary

c. lozenges
d. tablets
7. The following are parenteral routes of drug administration except.
a. Sub-cutaneous
b. Intraperitoneal
c. Sublingual
d. Intravenous
8. Drugs given through one of the following routes undergo the first pass effect.
a. Oral
b. Inhalation
c. Buccal
d. Sublingual
9. What is not an appropriate action when a patient, who is legally responsible
for their care, refuses a medication?
a. Notify the ordering physician of patient’s refusal to take medication.
b. Document the patient’s refusal to take medication and education that
you provided.
c. Explain the consequences for not taking the medication.
d. Force the patient to take it anyway.
10. What is the minimum amount of times that you should check the
medication label before administering the medication.
a. 1
b. 2
c. 3
d. 4
11. The nurse takes an 8 am medication to the patient and properly identifies
her. The patient asks the nurse to leave the medication on the bed side table
and states that she will take it with breakfast when it comes. What is the best
response to this request?
a. Leave the medication and return later to make sure that it was taken.
b. Tell her that it is against the rules, and take the medication with you.
c. Tell her that you cannot leave the medication but will return with it
when breakfast arrives
d. Take the drug from the room and record and record it as refused
12. Which of the following is not a common route for administering
medication
a. Oral

Final general pharmacology notes by Obin Abraham Olaka, St. Mary's hospital lacor, Gulu city , northern Uganda

Final general pharmacology notes by Obin Abraham Olaka, St. Mary's hospital lacor, Gulu city , northern Uganda

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Final general pharmacology notes by Obin Abraham Olaka, St. Mary's hospital lacor, Gulu city , northern Uganda