Introduction to pharmacology- Mr. Panneh

MR. ABDOU MARAM PANNEH
(RM ,FWACN,NT, RN)

DEFINITION OF PHARMACOLOGY:
 PHARMACOLOGY -Is the study of substances called DRUGS, which
bring beneficial changes in biological function when they interact with
living systems through chemical processes.
 Approximately, 10 million different drugs are available in the market.
DRUGS:- are chemical substances mainly produced for the following
purposes:-
 To prevent or avoid illnesses. E.g.. Antimalarials, Hormones,
Antibiotics, etc.
 To relief or treat illnesses. E.g...Antipyretics, Analgesics, etc.
 To diagnose illness: E.g... Histamine, etc.
 To suppress a cause or course of illness: E.g.…Antihypertensive,
Antibiotics, Antiulcers, etc.
Drug interaction occurs in two ways.
 Drug on the living organism referred to as PHARMACO-DYNAMICS
 Living organism on the drug referred to as PHARMACO-KINETICS.

ROLE OF THE NURSE
 Florence Nightingale (1854),pointed out that for a nurse
to be a professional, he/she must know the following;
 The PHARMACEUTICAL SOURCES and FORMS.
 PHARMACO-DYNAMICS and PHARMACO-KINETICS
 The SIX RIGHTS of drug administration.
 The PRESCRIPTION NOMENCULATURE.
 PHARMACOLOGY therefore, comprises of the physical
and chemical processes and the sources compounding the
physiological actions, absorption, distribution, bio-
transformation or metabolism, excretion and therapeutic
uses of the drugs to recognize and registered adverse drug
reactions.

PHARMACEUTICAL SOURCES:-
These are sources from which drugs are derived. There
are 2 main sources:
I) NATURAL:
 Plants (flowers, leaves, fruits, roots, seeds, stalk, etc.)
 Animal (tissues, secretions, etc..)
 Minerals:- Pure (cobalt, uranium)
- Salts (ferric iron, calcium carbonate)
II) ARTIFICIAL OR SYNTHETIC:
 Completely
 Partially (through laboratory).

B. PHARMACEUTICAL FORMS:
 They are a secure and suitable drug formulation which
can be employed in medical practice
They depend on:
 Drug’s source.
 Physiochemical drug´s properties
 Biochemical and physiological properties of living
systems.
 Treatment’s purpose (Prophylaxis, relief, diagnosis).
 Ossification: Dose- drug quantity that will produce the
desired therapeutic effect.
 Route of administration.

Cont’d:
 There are 4 main types of pharmaceutical forms.
They are:
 Liquids forms.
 Solid forms.
 Soft or semisolid forms.
 Gas or inhalations forms (Includes preparations
generally for bronchial or pulmonary route): Aerosols,
Spray, Nebulizers or Inhalers, Volatiles liquids,
Gaseous substances.

Cont’d
I. LIQUIDS FORMS:
 These include preparations for different routes of
administration.
SOLUTIONS: Substances dissolved in water, alcohol or mix
water- alcohol. They are usually transparent. Eg.
TINCTURES: Alcohol extract of animal or vegetable substances.
They must be colorant as part of the substance they are made
from. Eg Iodine Tincture.
INFUSIONS: Soft parts of vegetables extracted in boiling water.
Eg. Ringer’s Lactate, 5% Dextrose, 0.9% Normal Saline.
DECOCTAS: Hard parts of vegetables or plant extracted in
boiling water. Eg. Seeds in cell.
EXTRACTS: Fluids, soft or dried extracted with special
procedures. Eg. Cocoa (Nescafe) extract.

Cont’d :
SUSPENSIONS: Substances insoluble in water and is
necessary to shake well before they are dissolved for
administration. Eg. Magnesium Sulphate.
EMULSIONS: Fats or oils suspended in a liquid with an
emulsifier. Eg. Aqueous Cream.
MAGMAS: Milky suspensions.
GELS: Suspensions of insoluble substances. They are of high
hydrophilic base suitable for application on the face. Eg.
Top gel
For injection: AMPOULES, VIALS, CARTRIDGES,
BOTTLES (glass or plastic):- These are containers used to
store the drug either in liquid, powder or suspension form.
Eg. Ampoule (chloroquine ampoule), Vial (procain
Penicillin vial), Bottle (ampicillin syrup bottle)

Cont’d:
II. SOFT FORMS:
 These include preparations only for topical route.
LINIMENTS: Liquid suspensions for lubrication and applied by
rubbing. Eg. Nerve & Bone liniment.
LOTIONS: Liquid suspensions of insoluble powder and water
suitable for application on hairy areas. Eg. Calamine Lotion.
OINTMENTS: Semisolid medicine in greasy base. Eg. Neomycin
ointment.
PASTES: Thick ointments with no more than 25% of powders. Eg.
Colgate tooth pastes.
CREAMS: emulsions containing an aqueous and an oily base, with
no more than 5% powders. Eg. Clotrimazole Cream.
SUPPOSITORIES: Medicinal substances mixed with a firm but
malleable base designed to dissolve when in moist environment
like the rectum. EG. Anusol (antihaemorrhoidal) suppositories.
PESSARIES: These are semi-solid form of preparations designed to
dissolve when in moist areas like the vagina. Eg. Nystatin Vaginal
Pessaries.

Cont’d :III. SOLID FORMS:
 These include preparations generally for oral route
administration.
TABLETS: Powdered drug that is compressed and molded into
small disk designed to be taken orally. Eg. Paracetamol
Tablets.
PILLS: These are small round tablet-form substances that need
to be swallowed wholly. Eg. Microgynon F/P pills.
CAPSULES: Gelatin-covered substance in dried form and
contains the drug inside. Eg. Tetracycline capsule.
TROCHES: These are Lozenges that dissolve in the mouth. Eg.
Strepsils, mints.
GRANULES: Dry powdered drugs. Eg. Neomycin-bactricin
powder.
POWDERS: These are dry form of substances. They help to
reduce friction between opposing skin and reduces heat. They
should not be applied on moist areas because they can cake
and abrade skin.

Cont’d :
IV. GAS OR INHALATION FORMS:
 These includes preparations generally for pulmonary
route
AEROSOLS: In sprays, nebulizers or inhalers with or
without a propellant.
VOLATILES LIQUIDS for general anesthesia.
GASEOUS SUBSTANCES for general anesthesia.

Cont’d :
DRUG NAMES:
Drugs often have two names.
 NON- PROPRIETARY NAME OR GENERIC NAME:
Is used in Pharmacopoeias, Pharmaceutical code
Drug’s Formulary, etc. They are the chemical or
pharmacological names internationally accepted
based principally on the chemical structure.
 TRADE, BRAND OR COMMERCIAL NAMES: When
the drugs are specially combined in specific
therapeutic formula or composition. The names are
officially registered with trade mark.

PHARMACO-DYNAMICS
 This is the first branch of Pharmacology. It is the study of
drug action and its interaction with the action site or other
drugs.
 It includes the most important drug’s actions and observed
drugs effects.
 Drug interaction with the action site is a process referred to
as the drug’s Mode or Mechanism of action.
 These effects determines the group in which each drug is
classified according to illnesses and often play the major
role in the decision whether that group is the appropriate
therapy for a particular symptom, syndrome or disease.
 Also, it determines the characteristics of the drug
employment (Prevent- Relief- Diagnose or Treatment).

PHARMACODYNAMICS Cont’d..
PHASES OF DRUG ACTION:
There are 3 phases of drug action.
 I. PHARMACEUTICAL PHASE:- This refers to the
prescriptions and administrations of drugs. This must
be done by taking serious consideration for the right
drug, dose, time, route, right patient and the patient’s
right for consent, so that the drug can reach the
desired effect.
 The prescriber´s order addresses to pharmacist to
prepare or dispense specific medication for specific
patient. Writing a prescription should be based on a
series of rational elements considered in the first
phase of drug activity.

2. PHARMACODYNAMICS Cont’d..
II. PHARMACOKINETIC PHASE:- It includes several
processes as absorption, distribution, metabolism and
excretion of drugs. The principal objective is to make the
drugs reach its site of action in the right concentration. The
prescriber have a great practical role in the choice and
prescription of a particular drug for the patient. Therefore
pharmacokinetic interaction determines route of
administration, frequency and other particular moment in
the action of drugs.
III. PHARMACEUTICAL PHASE: This refers to the drugs
interaction or effect. There are two types of drug effect.
 Chemical Effect: - Is the drug action on the action site.
 Therapeutic Effect: - Is the drug action on the organism.

DRUG DOSE:
This is the total drug quantity or target concentration that
will produce the desired therapeutic effect.
TYPES OF DRUG DOSAGES:
 Single Dose:- This is when the drug is administered only
once. Eg. Stat dose.
 Total dose:- Is the sum of the given in a course of
treatment.
 Loading Dose:- This is the initial amount of the drug
given promptly in high concentration to control an effect.
 Maintenance Dose:- Is when the drug is given to
maintain a steady state.
 Toxic Dose:- This is the amount of the dose given that
becomes higher than the required amount causing an
adverse effect.

DRUG ACTION:
 This is the ability of the drug to create a chemical action.
TYPES OF DRUG ACTION:
 Excitatory Action: - Is an increase in the response of the
drug in the Central Nervous System.
 Inhibitory Action:-Is a decrease in the response of the
drug in the Central Nervous system.
 Irritatory Action: - Is the maximum excitatory action.
 Replacement Action: - Is when the drug is given to
replace a function.

SITES OF DRUG ACTION:
 Receptors:- These are macro-molecular components or
biochemical reactivity structures performed or previously
synthesized. Receptors pose variable stereo-specificity.
They are present in high concentration in tissues and
organs.
 Endogenous signaling Products: - these are proteins,
hormones, enzymes, nervous transmitters, etc… These
products stimulate the individual to maintain a
homeostatic physiologic process.
 Exogenous Signaling Products: - These are all the other
drugs administered when the endogenous signaling
products are lower or ineffective. Eg. Adrenalin, insulin,
oxytocin, etc.

PHARMACEUTICAL DRUG PROPERTIES:
This refers to the way in which binds with the receptor site.
Drug-receptor interactions
 Affinity: Tendency to bind to receptors.
 Efficacy: Ability of the drug, once bound to initiate changes
that lead to effects.
 Agonists: It is have affinity and high efficacy, initiate changes
in cell function, producing effects of various types.
 Antagonists: The drug binds to the receptor without causing
activation and thereby prevents the agonist from binding
(Have affinity but not efficacy)
 Full agonists: Which can produce maximal effects?
 Partial agonists: Which can produce only sub maximal
effects, have intermediate efficacy?

DRUG ANTAGONISM.
 Chemical antagonism (interaction in solution)
 Pharmacokinetic antagonism (one drug affecting
the absorption, metabolism or excretion of the other)
 Competitive antagonism (both drugs binding to the
same receptors, can be reversible or irreversible)
 Non-competitive antagonism (the antagonist
interrupts receptor-effector’s linkage)
 Physiological antagonism (two agents producing
opposing physiological effects).

ADVERSE DRUG REACTIONS AND DRUG INTERACTIONS
 In Pharmacotherapeutics, a drug typically produces numerous
effects, but usually ONLY ONE is sought as the primary goal of
treatment. Most of the others effects are referred to as
undesirable effects of drug for that therapeutic indication and
doses and conform the named Adverse Drug reaction.
ADVERSE DRUG REACTIONS
 Is a harmful, undesirable response which may result from any
clinically useful drug in its therapeutic dose?
 They may be common or rare and mild, severe or life-
threatening.
 They may occur after the first dose, after several doses or after
many doses.
 An adverse reaction often is unpredictable, although some drugs
are known to cause certain adverse reactions in many patients.

Predisposing Factors that lead to Adverse Drug Reaction.
 Extremes of age: Infants have lack enzymes and a decrease of
renal blood flow. In the elderly there are a decrease of the blood
flow in all organs especially liver and kidneys.
 Extremes of body weight or body mass: The extremely thin
or obese patient requires an individual dosage.
 Genetic factors: Lack and deficiency or the reverse, fast activity
of metabolic enzymes may be as a result an ADR.
 Some pathological conditions (gastric surgery or intestinal
malabsorption, Infective diarrhoea or oedema of the gut,
impaired renal function, impaired hepatic function, poor
nutrition).
 Changes associated with special physiological status
(Pregnancy).

TYPES OF ADVERSE DRUG REACTION
There are two main types of Adverse Drug Reaction.
Dose Dependent Drug Reaction:-These are generally
predictable. It often results from a known pharmacological
effect of the drug where a large dose of the drug is given over
a long period of time and one may expect a reaction.
Examples:
 - Gout resulting from treatment with a Thiazide diuretic.
 - Bone narrow suppression following therapy with
Methptrexate.
Dose Independent Drug Reaction:- These are generally
unpredictable. In these reactions there is a large variability
between individuals in their susceptibility to an adverse
effect

HYPERSENSITIVITY
This is an exaggerated or appropriate immune response causing tissue
damage.
TYPES OF HYPERSENSITIVITY
 Allergic Drug reactions:
 May occur the first time a drug is given if the patient had received the
drug in the past or after more than one dose of the drug has been given.
 Occurs because the individual’s immune system views the drug as a
foreign substance, or antigen. The recognition of an antigen stimulates
the antigen-antibody response that prompts the body to produce
antibodies, which are immune system molecules that react with the
antigen. If the patient takes the drug after the antigen-antibody response
has occurred, then an allergic reaction results.
 Type I- Anaphylactic reactions.
 Type II- Complement activation.
 Type III- Immune complex reaction.
 Type IV- Cell mediated Hypersensitivity.

Examples of some allergic signs and symptoms.
 Itching, skin rashes, and hives (Urticaria), difficulty breathing,
wheezing, cyanosis, a sudden loss of consciousness, and swelling
of eyes, lips or tongue
 Anaphylactic shock is an extremely serious allergic reaction that
usually occurs soon after the administration of a drug to which
the individual is sensitive. This type of allergic reaction requires
immediate medical attention. Can be fatal if it not recognized
and treated immediately.
Signs and Symptoms of anaphylactic Shock:
 Respiratory: Bronchospasm, Dyspnea (difficult breathing),
Feeling of fullness in the throat, Cough, Wheezing.
 Cardiovascular: Extremely low blood pressure, Tachycardia
(heart rate > 100 b/m), Palpations, Syncope (fainting), Cardiac
arrest.
 Integumentry: Urticaria (rash), Angioedema, Pruritus (itching),
Sweating.
 Gastrointestinal: Nausea, Vomiting, Abdominal pain.

Drugs most likely cause Anaphylactic reaction are:
 Penicillins and cephalosporins
 Vaccines
 Insulin
 Streptokinase
 Asparaginase
 Heparin
 Dextrans
 Neuromuscular blocking drugs.
 Radiological contrast agents

Anaphylaxis is treated with drugs consider acting
pathphysiological status like:
 Adrenaline (Epinephrine): Hypotension and
Bronchoconstriction
 Corticosteroids: Swelling and urticarial rash.
 Antihistaminic drugs
 2. Idiosyncratic Reaction: Refers to any unusual or
abnormal reaction to a drug. It is any reaction that is
different from the one normally expected from specific
drug and dose. The cause of drug idiosyncrasies is not
clear; they are believed to occur because of a genetic
deficiency that makes a patient unable to tolerate certain
chemicals, including drugs.
 - occurs when a patient has contact with a drug and have
immediate death.

Drug Idiosyncrasy
 Eg. The speed of reaction of the N-acethyltransferase
enzyme determine the slow and rapid acethylators of
Isoniazide, Hydralazine, Phenelzine, Dapsone,
Sulphamides and Procainamide. In the slow ones
(hepatotoxicity caused by Isoniazide), in the rapid
ones (systemic lupus erythematosus caused by
Isoniazide, Hydralazine and Procainamide).
 Eg. Individuals with glucose-6-phosphate
dehydrogenase (G6PD) deficiency have abnormal
reactions to a number of drugs, these patients
experience varying degrees of hemolysis (destruction
of red blood cells) if they take these drugs include
Aspirin, Chloramphenicol and Sulphonamides.

3. Pseudoallergic Reactions: These reactions have
similarity to those of allergic reactions but are not
involve immune recognition. They are due to release of
immunological mediators by other mechanisms. They
typically occur on first time exposure to the drug
rather than after previous sensitization.
Examples:
 Itching, bronchospasm and vasodilatation following
treatment with intravenous Morphine.
 Flushing, Urticaria, bronchospasm and even
circulatory shock caused by Aspirin.

4. Paradoxical effect: When the expected effect is reversed
and the patient suffer other unexpected effect
5. Iatrogenic drug effect: When the adverse drug reaction
depend of the physician, pharmacist or nurse.
6. Drug Tolerance Reaction: Is a decreased response to a
drug, requiring an increase in dosage to achieve the
desired effect. May be developed when a patient takes
certain drug, such as a narcotic or tranquilizer for a long
time. Is a sign of drug dependence.
7. Drug Dependence: It can be physical or psychological
and patient’s need for the drug to reverse unpleasant
symptoms is unavoidable.
8. Tachyphylaxis: The effect of a drug gradually diminishes
when it is given continuously or repeatedly.

9. Undesirable or side or collateral effect: When the
undesirable effect cannot be avoided although the doses
are diminished. In some patients with other ill situation
this effect can be desirable.
10. Toxic Reactions: Most drugs can produce toxic or
harmful reactions if administered in large dosages or when
blood concentration levels exceed the therapeutic level.
Toxic levels may also build if the patient’s kidneys are not
functioning properly and can not excrete the drug. Some
toxic effects are immediately visible, others may not be
seen for weeks or months.
Some drugs have a narrow margin of safety (Digoxin,
Lithium), even when given in recommended dosages. It is
important to monitor these drugs closely to avoid toxicity.

 Drug toxicity can be reversible or irreversible, depending on
the organs involved.
 Damage to the liver may be reversible because liver cells can
regenerate. Hearing loss caused by damage to the eighth
cranial nerve caused by toxic reaction to the anti-infective
drug Streptomycin.
11. Delayed Toxicity:- Occurs when the undesired effects of a
drug appear several days to years after administration of the
drug.
12. Cumulative Drug Effect: May occur in patients with liver
or kidney disease because these organs are the major sites for
the breakdown and excretion of most metabolize and excrete
one (normal) dose of a drug before the next dose is given.
Can be serious because too much of the drug can accumulate
in the body and lead to toxicity.

13. Excessive Therapeutic Reaction:- Occurs most commonly
from miscalculations in which an over-dose of the drug is
administered.
14. Pharmacogenetic Reactions: A Pharmacogenetic disorder
is a genetically caused abnormal response to normal doses of
a drug.
This abnormal response occurs because of inherited traits that
cause abnormal metabolism of a drug.
For example, individuals with glucose-6-phosphate
dehydrogenase (G6PD) deficiency have abnormal reactions to
a number of drugs, these patients experience varying degrees
of haemolysis (destruction of red blood cells) if they take
these drugs.
Examples of drugs that cause haemolysis in patients with a
G6PD deficiency include Aspirin, Chloramphenicol and the
Sulphonamides.

15. Anaphylactic shock:- Is an extremely serious
allergic reaction that usually occurs soon after the
administration of a drug to which the individual is
sensitive.
 This type of allergic reaction requires immediate
medical attention.
 It can be very fatal if not recognized and treated
immediately.

DRUG INTERACTIONS
 Health care workers involved in patient care should be aware of
the various drug interactions that can occur, most importantly
drug-drug interactions and drug-food interactions.
i) Drug-Drug Interactions:- occurs when one drug interacts
with or interferes with the action of another drug.
For example, taking an antacid with oral Tetracycline causes a
decrease in the effectiveness of the Tetracycline.
Drugs known to cause interactions include oral anticoagulants,
oral hypoglycemics, anti-infectives, antiarrhythmics, cardiac
glycosides, and alcohol.
Drug-drug interactions can produce effects that are additive,
synergistic, or antagonistic.

ii) Additive Drug Reaction: Occurs when the
combined effect of two drugs is equal to the sum of
each drug given alone. For example: Heparin with
alcohol will increase bleeding. (1+1=2)
iii) Synergistic Drug Reaction: Occurs when drugs
interact with each other and produce an effect that is
greater than the sum of their separate actions. For
example: Hypnotic drug and alcohol, the action of the
hypnotic increases. (1+1=4)
iv) Antagonistic Drug Reaction: Occurs when one
drug interferes with the action of another, causing
neutralization or a decrease in the effect of one drug.
For example: Protamine sulfate is a heparin antagonist.

v) Drug-Food Interactions: When a drug is given orally,
food may impair or enhance its absorption.
A drug taken on an empty stomach is absorbed into the
bloodstream at a faster rate than when taken with food in
the stomach.
Some drugs must be taken on an empty stomach to achieve an
optimal effect (They should be taken 1 hour before or 2
hours after meals).
Drugs that irritate the stomach (nausea, vomiting or
epigastric distress), are best given with food or meals to
minimize gastric irritation.
For example: Nonsteroidal anti-inflammatory drugs and
salicylates.

TOXICOLOGY.
 This is the study harmful effects of chemical substances
and their mechanism of action on living organisms.
 It is concerned not only with drugs used in therapy but also
with all other chemical substances.
 All drugs are poisonous and there is no single substance
that is not poisonous. The right dose differentiates the
poison and the remedy.
 The very toxic may be less harmful if given in the right
dose, time, route, interval and to the right person.
WHAT IS POISON
 A Poison is a chemical substance which is capable of
causing harm to a living organism even when give in a very
small quantity.

SPECIALIZED AREAS OF TOXICOLOGY IMPORTANT IN
MEDICINE
1. CLINICAL TOXICOLOGY:- Is concerned with the treating
of patients who are poisoned with chemicals or drugs, and
the also with the development of new techniques.
2. FORENSIC TOXICOLOGY:- Is concerned with the
medico-legal aspects on the damage caused by any
substance.
3. PRE-CLINICAL or EXPERIMENTAL TOXICOLOGY:- Is
concerned with the study and identification of all changes
caused by chemical substances given in appropriate doses,
amount or concentration in living organisms.( side-effects
caused by drugs)

 PRINCIPLES OF PREVENTION OF POISONING:-
 All chemical substances should be kept in their original labelled
containers.
 Keep all substances, drugs, pesticides and potentially hazardous
household chemical out of sight and reach of children.
 Discard all empty containers safely.
 Do not mix household and garden chemicals together.
 When administering medicines to children, do not refer to it as
candy.
 Before taking or using any chemical, read the label or directions
carefully.
 Always use or take medicines in a well ventilated and lighted place.
 Avoid storage of potentially toxic or hazardous substances in food
containers.
 All chemicals should be kept in a locked up cabin and labelled.
 Do not mix chemical together.

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3. PHARMACOKINETICS
 This is the second branch of Pharmacology. It is the study
of drug administration, absorption, distribution,
metabolism (biotransformation) and excretion.
 The absorption, distribution, metabolism, and excretion of
a drug all involves its passage across cell membranes.
DRUG ADMINISTRATION
 This is the act of introducing a drug into the body.
 ROUTES OF ADMINISTRATION
 They are the way which permits to obtain a desirable drug
concentration in the site of action, the moment and the
duration of action.
 Clinical practitioners employ 5 main types of drug
administration.

3. PHARMACOKINETICS Cont’d..
I) ENTERAL ROUTE:
 This includes Oral, sublingual and rectal administration.
ADVANTAGES
 It´s safe
 Most convenient or suitable.
 Most economical.
 Most easy
DISADVANTAGES
 Limited absorption of some drugs.
 Gastrointestinal disturbances.
 Cannot be used on unconscious, dysphagic or clients with gastric
suction.
 Destruction of some drugs by digestive enzyme, by low gastric pH,
intestinal flora or by the liver.
 Interaction with foods.
 Patient cooperation is highly required.

II) PARENTERAL ROUTE:
 Includes intravenously, intramuscular, Subcutaneous,
Intradermal, Intrarterial and other similar routes which you use
hypodermic syringe.
ADVANTAGES
 Usually availability is more rapid, extensive and predictable.
 The effective dose can be more accurately.
 It is useful when the patient is unconscious.
DISADVANTAGES
 Pain may accompany the injection.
 Asepsis or sterilization must be maintained.
 After administration you can not elicit or retrieve back the drug.
 It’s sometimes difficult for patients to perform the injections
themselves.
 The drugs are more expensive.
 In our countries if the patient live in a far away region have to
travel several miles or Km to receive injection

III) TOPICAL ROUTE:
 When we apply the drug on the body surface like skin,
mucous membrane except of the digestive tract (vagina,
urethra) or in special sites as eyes, ears, nose and so on.
 The main objective is to produce local effects. Eventually
systemic absorption is the goal.
 Is necessary to take into account if the skin or mucous
membrane are intact or not, because if the skin or mucous
is abraded, burned or other similar condition’s the
increased blood flow also enhance drug absorption.
ADVANTAGES
 There is less side-effects
 Easy to apply
DISADVANTAGES
 Requires proper diagnosis
 Absorption may be slow

IV) INHALATION OR PULMONARY ROUTE:
 When the drugs achieve the action site through respiratory
tract.
 Gaseous and volatile drugs may be inhaled and absorbed
through the respiratory tract mucous membrane and
pulmonary epithelium. Access to the blood flow is rapid,
because the lungs surface area is larger.
ADVANTAGES
 Instantaneous absorption of a drug into the blood.
 Avoidance of hepatic first pass loss.
 Drugs local actions in bronchial or pulmonary disease.
DISADVANTAGES
 Poor ability to regulate the doses.
 Necessary specialize equipment.
 Cumbersome administration method.

DRUG ABSORPTION MECHANISM:
 The passage of the drug from its site of administration into the plasma. This
occurs in weak, acid or base form. Many factors are involved in this process.
Factors affect the drugs absorption
 Surface area for absorption: The upper intestine provide an extremely large
surface area, approximately 200 m2 . Accordingly the rate of drug absorption
from the intestine is great
 Blood flow to the site of absorption: Blood flow increase in the absorption
site raise the speed of drug absorption (For example: The addition of
vasoconstrictor drugs in the local anesthetic)
 The physical state of the drug (solution, suspension, solid form): The drugs
must be dissolved in the site of administration to could be absorbed
 Its water solubility: The drugs can be hydrophilic when they are dissolved in
water, lipophyllyc when they are dissolved in lipid medium like cell wall
 Concentration at the site of absorption: high concentration of drugs are
absorbed more rapidly than they are in low concentration

 Interactions with others drugs or foods: The may occur in
compliance with the physicochemical drug properties, for example:
tetracycline with drugs containing Ca++ or milk as food
ROUTE OF ADMINISTRATION.
 Absorption is favored when the drug is in the nonionized and
more lipophilic form.
 Bioavailability: Is the percentage or fraction of the administered dose
that reaches its site of action or the systemic circulation of the patient
following administration.
 This Can be altered by the following factors:
 Drug Dissolution speed.
 Area of Absorption.
 Chemical form.
 Dose form.
 Route of administration.
 The stability of the active ingredient in the gastrointestinal tract.
 Drugs metabolism before reaching the systemic circulation.

 DRUG TRANSPORT MECHANISM
i) Passive Transport:- This is when the drug moves in
favor of concentration in gravity. That is, from internal
to external. There is usually weak interaction.
ii) Active Transport:- This is when the drug moves
according to the lowering of concentration. That is,
from external to internal. There is strong
concentration.

DRUG DISTRIBUTION MECHANISM:
 Following absorption into the systemic blood, a drug is
distributes into interstitial and intracellular fluids.
Factors affecting drug distribution
 Physicochemical drug properties.
 Parturition coefficient lipid/water tissue/blood.
 Cardiac output and vascular perfusion.
 Cell membrane permeability (Blood-brain barrier,
placental transfer drugs)
Plasma proteins
 Many drugs are bound to plasma proteins, mostly to
plasma albumin for acidic drugs and to α1 acidic
glycoprotein for basic drugs.
 The fraction of total drug in plasma that is bound is
determined by the drug concentration, its affinity for the
binding sites, and the number of binding sites.

 Tissue binding.
 Many drugs accumulate in tissues at higher
concentrations than those in the extracellular fluids
and blood.
 Liver: Quinacrine during long-term administration.
 Fat: Barbiturate, thiopental.
 Bone: Tetracycline, heavy metal.

DRUG METABOLISM MECHANISM:
 It is the ability of the living organism to metabolize
drugs; the principal objective is to transformer the
drug to more polar, inactive metabolites for the
elimination from the body and termination of their
biological activity.
Site of biotransformation
 The enzyme systems (microsomes P-450 family),
involved in the biotransformation of drugs are
localized in the liver
 Other organs with significant metabolic capacity
include: Gastrointestinal tract, Kidneys, Lungs.

FACTORS AFFECTING METABOLISM.
i) Genetic variation: In compliance with individual differences in
metabolic rate, really it depends on the nature of the drug itself,
but it depends too on the genetic factors.
ii) Environmental determinants: Many substances like drugs
and foods may induces or inhibit microsomal enzymes and
consequently the metabolism of other drugs,
iii) Disease factors: Diseases can predispose towards
pharmacokinetic disturbance (The absorption can be altered in
gastrointestinal diseases; Metabolism of many drugs is largely
dependent on normal hepatic function and extreme caution
must be taken in administering to patients with liver failure and
others).
iv) Age and sex: Increased susceptibility to the drugs has been
reported in very young babies and children and in old patients as
compare to young adults. Some sex-related differences in drug-
metabolizing activity.

DRUG EXCRETION MECHANISM:
 Drugs are eliminated from the body either unchanged by the
process of excretion or converted to metabolites.
 Excretory organs, the lung excluded, eliminate polar
compounds more efficiently than substances with high lipid
solubility. Lipid-soluble drugs thus are not readily eliminated
until they are metabolized to more polar compounds.
Drugs that are excreted largely unchanged in the urine
include:
 100-75% Frusemide, gentamycin, methotrexate, atenolol,
digoxin
 75-50% Benzylpenicillin, cimetidine, oxytetracycline,
neostigmine
 ~50% Propantheline, tubocurarine

EXCRETORY PATHWAYS.
 Renal excretion.
 Biliary and fecal excretion.
 Others route: Sweat, saliva, tears, breast milk, semen, expaired air.
 Biliary Excretion & Entero-hepatic Re-cycling
 Numerous hydrophylic (polar) drug conjugates (particularly
glucuronides) are excreted into the bile, and delivered to the intestine.
 The glucuronides are mostly hydrolysed to yield free drug within the
ileum.
 Free drug may then be re-absorbed in the terminal ileum (the site of
absorption of numerous molecules, including Vit A, D and K, and the
bile acids).
 The reservoir of “re-circulating drug” may be as much as 20% of the
total drug in the body.
 Examples of drugs that undergo entero-hepatic re-cycling include
morphine and ethinylestradiol.

3. THE RIGHTS OF DRUG ADMINISTRATION:
 Florence Nightingale was the one who came up with these rights
she first identified as five. These were later updated to 6 Rights
 These rights are:-
THE RIGHT PATIENT
 The right patient must be first identified. This can be done by
asking the patient to state his/her and comparing it with the
case/prescription note.
 Ensure that the patient’s condition requires him/her to use the
drug.
THE RIGHT DRUG:
 Ensure that the right drug is given to the patient. This can be
done by checking the prescription made against the drug at
hand.
 Check for the expiry date of the drug
 Involve a second trained nurse to confirm the drug.

THE RIGHT DOSAGE:
 Ensure that the right dosage is administered to the patient.
 Where necessary, calculate the dosage to get the appropriate prescribed
dose.
 This can be done by dividing the prescribed dose by the drug dosage form
available and multiplied by the amount of milliliters (in case of injections or
syrups).
 Remember that in children, the dosage is prescribed using body weight, age
or height.
THE RIGHT ROUTE:
 Ensure the drug is administered in the right route as prescribed..
 This can be in the form of Enteral (oral, rectal, etc), Parental,(intramuscular,
Intradermal, intravenous,etc), Topical or Inhalatory.
THE RIGHT TIME:
 Ensure that the drug is administered at the right time.
 This can be done by comparing the existing time to the time ordered for the
drug to be administered.
 Ensure that the interval is correct.

THE RIGHT OF PATIENT FOR CONSENT:
 Remember that the patient has the right to accept or
deny for administration of any drug and this should be
used as a value judgment or punishment for further
care.
 The patient should be well informed about the drug
(use, mode of action, side-effects, etc) before
administration and he/she must first accept.

4. PRESCRIPTION NOMENCLATURES
 The common prescription nomenclature used in clinical practice
includes the following:
 1/7, 2/7, 3/7, 4/7, etc-- …......... 0ne day, two days, three days, four
days, etc…
 1/52, 2/52, 3/52, 4/52, etc.. …..one week, two weeks, three weeks, four
weeks, etc..
 X …………………………………for
 SOS, PRN ……………………….when necessary
 S/C or SQ or SubQ ……………Subcutaneous
 IM …………………………………Intramuscular
 ID ……………………………….Intradermal
 DLY……………………………….Daily
 d ………………………………….day
 DYS………………………………..days

 DC or D/C …………………………Discontinue
 DX, Dx…………………………… Diagnosis
 I&D ………………………………..Incision and drainage
 C/o ……………………………….Complained of
 CC………………………………..chief complain
 AM, OM ……………………………….Every morning
 An, ON ……………………………..Every night
 SID or sid or qd………………………..every day
 MN………………………….midnight
 NPO……………………………..nil per oral
 AC ……………………………………before meal
 Asa………………………………….Aspirin
 ASAP/asap……………………….as soon as possible
 BIB/bib ……………………………….bibe=drink
 Nocte ……………………………….Nightly
 AQ,H20 ……………………………….Water
 BOLUS …………………………..A large single dose

 Cap, Caps ……………………….Capsule (s)
 C ……………………………….. with
 E …………………………………. the
 TAB, TABS………………………….Tablet (s)
 i, ii, iii, iv, v………………………….one, two, three, four, etc tablets
 BD, BID…………………………. Twice or two times a day
 TDS, TID …………………………Three times a day
 QDS, QID ………………………..Four times a day
 SID, sid…………………………..every day
 DXor Dx…………………………..diagnosis
 h………………………………hour
 HR……………………………..heart rate
 HS………………………………..at bed time
 RX, Tx………………………………Treatment
 Sx………………………………..symptoms
 R/O……………………………rule out

 MX ………………………………..Management
 Gutt, Gtt ……………………………Drops
 Stat ………………………………..Immediately
 PO …………………………………….Per Oral
 POD ………………………………..Post Operative Day
 Pt……………………………………..patient
 Pn…………………………………pain
 Pr or PR …………………………..Per rectum
 Pre-op …………………………..prior to surgery
 Alt or QOD ……………………Alternate or every other day
 D & C ……………………………Dilatation and Curettage
 D5W ……………………………..Dextrose 5% Water
 N/S ………………………………….Normal Saline

 R/L ………………………………….Ringer’s Lactate
 Mls …………………………………….Milliliter
 ACE ………………………………….Angiotensin Converting Enzyme
 ARC ………………………………..Aids Related Complex
 O2 …………………………………….Oxygen
 0C …………………………………….Degree Celsius
 Hb ……………………………………..Hemoglobin
 HLA ………………………………………Human Lymphocytes Antigen
 Mmol ……………………………………..Millimol
 mmHg …………………………………….Milliliter per mercury
 Min ……………………………………….Minute
 QS, Qv ………………………………….As much as possible
 H20 …………………………………….Water
 O/E ………………………………….On Examination
 ADR ……………………………………Adverse Drug Reaction
 DC or D/C …………………………Discontinue

 Vs, V/S………………………………….Vital Signs
 Vss………………………………………Vital Signs Stable.
 TPR & B/P………………Temperature, Pulse, Respiration
and Blood Pressure.
 SOB ………………………………..Shortness of Breath
 SOBE…………………………Shortness of breath on exertion
 Ud……………………………..as directed
 R/O……………………………..Rule out
 Sz…………………………………….. Seizure.
 SO ………………………………..HIV sero negative
 S1 …………………………………HIV 1 sero positive
 S3 ………………………………… HIV 1& 2 sero positive

 REFERENCES
 Basic and Clinical Pharmacology. Bertram G. Katzung.
 Pharmacology. H. P Rang, M. M. Dale, J. M. Ritter, P. K.
Moore.
 Pharmacology. 2005. Lippincott Willians and Wilkins.
 Basic Clinical Pharmacokinetics. Fourth Edition.
Lippincott Willians and Wilkins.
 British National Formulary 2009, London WC1H 9JP, UK
 Goodman and Gilman`s. The pharmacological basis
therapeutics.
 Morton J.R(BSN,PH.d.), Dorothy W.S.- Pharmacology and
drug therapy in nursing. J.B Lippicott company. Toronto,
USA.
 Hall.J.W.: Drug therapy in infectious diseases. Am.J.
Nursing, 61:56. 1961
 The Gambia Standard Drug Treatment Manual, MOHSW,
Banjul. July 2005

QUESTIONS,
CONTRIBUTIONS,
CLARIFICATIONS &
CONSTRUCTIVE
CRITICISMS?????

Introduction to pharmacology- Mr. Panneh

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