Introduction to general Pharmacology

UNIT-1:General pharmacology
Part : 1
Introduction to Pharmacology
Ms. Kanchan chouksey
Pharmacy, Medi-caps University, Indor
Email

BP 404 T Pharmacology I
 Unit I a. Introduction to Pharmacology
b. Pharmacokinetics
 Unit II a. Pharmacodynamics,
b. Adverse drug reaction,
c. Drug Interactions
d. Drug discovery and clinical evaluation of new drugs
 Unit III Pharmacology of drugs acting on Peripheral nervous system
 Unit IV Pharmacology of Drugs acting on Central Nervous system
 Unit V Pharmacology of Drugs acting on Central nervous system

Books
Text Books
 K.D. Tripathi A Text book of Pharmacology
 Sparsh gupta A textbook of Pharmacology
Reference Books
 Goodman and Gilman’s A Text book of Pharmacology
 Rang H.P., Dale M.M., A Text book of Pharmacology
 Lippincott A Textbook of Pharmacology
Other Books
Sharma H.L. , Sharma K.K., A textbook of Pharmacology,
and many others

Pharmacology :
Pharmacology is all about study of -
1.Drug
2.Drug effect
3.Body response to drug

The word pharmacology comes from the
Greek words :
 Pharmacon means : Drug / Medicine
 Logos means : To study

Continue:
 Pharmacology is the study of drugs including their
origins, history, uses, and properties.
 It mainly focuses on the actions of drugs on the body.

Definition :
In a broad sense, it deals with interaction of exogenously
administered chemical molecules with living systems, and any
single chemical substance which can produce a biological
response is a ' drug'.

Drug:
It is the single active chemical entity present in a medicine
that is used for diagnosis, prevention , treatment/cure of a
disease.

Clinically drugs used for:
 Diagnosis:Barium salts (Barium sulphate )
 Prevention: Vaccines/ chemoprophylaxis
 Treatment: Antibiotics, Disease, disorder
 Alteration of physiological processes: Hormones & their derivatives
(insulin, GH, contraceptive)
 Global effect: Generalanesthetics

Some terms related to Pharmacology:
 Drug – Drugs are substance which can change the physical and physiological
state
 Medicine- Medicine are the drug which are used to treat illness or discomfort
 Dose- Certain amount of drug
 Dosage Form- It is the Physical form of medicine

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 Onset of drug action : The time between drug administration and beginning
of therapeutic effect
 Duration of action : Time of drug to produce therapeutic effect
 Intensity of drug action : It is a maximum pharmacological response produce
by the peak concentration of drug
 Peak concentration (Cmax) : The point at which maximum concentration of
drug reached in plasma

The two main divisions of pharmacology are
Pharmacodynamics and Pharmacokinetics

1.Pharmacodynamics (Greek: dynamis -power)
What Drug Does With The Body :
 This includes physiological and biochemical effects of drugs and their
mechanism of action at organ system/subcellular/macromolecular levels
E.g.-
Adrenaline interaction with adrenoceptors G-protein mediated stimulation of
cell membrane bound adenylyl cyclase Increased intracellular cyclic AMP
cardiac stimulation, hyperglycaemia

Adrenaline interaction with adrenoceptors:

Adrenaline interaction with Adrenoceptors:

 This refers to movement of the drug in and alteration of the drug by
the body
 It includes absorption, distribution, binding/localization/storage,
biotransformation and excretion of the drug
2.Pharmacokinetics (Greek: Kinesis-movement)-
What The Body Does To The Drug

What The Body Does To The Drug:

History of Pharmacology:
 Knowledge of drugs and their uses in diseases are as old as history of mankind
 Primitive men gather the knowledge of healing and medicines by observing the
nature , noticing the animals while ill and personal experience after consuming
plants and herbs as remedies.
 They extracts from plants, animals and minerals had medicinal effects on body
tissue.
 These discoveries became the foundation of pharmacology.

Historical development in Pharmacology:
Hippocrates (460-375 BC) –
 A greek physician consider “father of medicine”
 He was the first person recognize disease as abnormal reaction of body
 He introduced use of metallic salts for the treatment of disease
Theophrastus (380-287 BC) –
 He called as “father of Pharmacognosy”
 He classified medicinal plants on the base of medicinal characteristics

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Dioscorides (AD 57) –
 He produced one of the first materia medica of
approximately 500 plants and remedies
Valerius cordus (1514-1544)-
 He compiled the first pharmacopeia where he
described techniques for the preparation of drugs.

Modern Pharmacology-
Conversion of old medicines into the modern
pharmacology start taking shape following the
introduction of animal experimentation and isolation of
active ingredients from plants

Landmarks of Modern Pharmacology:
Francois Megendie ( 1783- 1855) -
 He was the first pharmacologist established the foundation of modern pharmacology.
 He developed experiment to elucidate the physiological processes and action of drugs
on the body.
Frederich serturner -
 He was the German pharmacist’s assistant , isolated morphine – the first pure drug in
1805

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Ostwald schmiedeberg (1838-1921)- “father of Pharmacology” established
pharmacology as an independent discipline.
 In 1872 set up an institute of pharmacology in Strasbourg, France (Germany at
that time) which became a mecca for students who were interest in
pharmacological problems.

Basic areas of Pharmacology:
Pharmacokinetics: deals with absorption,distribution, biotransformation
& excretion of drugs.
Pharmacodynamics: study of biochemical & physiological
effects of drugs & theirMechanism of action.
Pharmacotherapeutics: use of drugs in prevention & treatment of
disease.

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Chemotherapy: effect of drugs upon microorganisms, and neoplastic cells living &
multiplying in living organism.
Toxicology: branch of pharmacology which dealswith the undesirable effects of
chemicals on living systems.

NATURE & SOURCES OF DRUGS:
1.Natural drugs-
Plants :
Many plants contain biologically active substances and are the oldest
source of drugs.
e.g. use of opium, belladonna, ephedra. cinchona. curare, foxglove,
sarpagandha,

Chemically the active ingredients of plants fall
in several categories:
a. Alkaloids:
• These are alkaline nitrogenous bases having potent activity, and are the
most important category of vegetable origin drugs.
• Prominent examples are:
morphine, atropine, ephedrine, nicotine, ergotamine, reserpine, quinine,
vincristine,

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.
b. Glycosides:
• Glycoside is a molecule in which a sugar is
bound to another functional group via a
glycosidic bond.
• Cardiac glycosides (Digoxin, Digitoxin) are the
best known glycosidic drugs.
• Aminoglycosides (gentamicin) are antibiotics
obtained from microorganisms

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2. Animals
Exploration of activity of organ extracts in
the late 19th and early 20th century that
led to introduction of animal products
into medicine
E.g. adrenaline, thyroxine, insulin, liver extract
(vit. B 12).
Antisera and few vaccines are also produced from
animals

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,
.
4. Synthetic drugs:
Prepared by chemical synthesis
in pharmaceutical laboratories.
E.g. Sulphonamides, quinolones
,barbiturates.
3. Microbes
Antibiotics are obtained from fungi,
actinomycetes and bacteria,
E.g. penicillin, gentamicin,
tetracycline, crythromycin,
polymyxin B.
Some enzymes-
E.g. diastase from a fungus and
streptokinase from streptococci
have a microbial source.
Vaccines are produced by the use
of microbes
5. Biosynthetic drugs:
Prepared by cloning of human DNA in
to the bacteria like E.coli.
E.g.Human insulin (humulin), human
GH.

ESSENTIAL MEDICINES (DRUGS) CONCEPT:
 The WHO has defined essential Medicines (drugs) as " those that satisfy the
priority healthcare needs of the population.”
They are selected on the basis of –
 Public health relevance- disease in country
 Evidence on safety and efficacy
 Comparative cost effective

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 WHO brought out its first Model List of Essential Drugs along with their
dosage forms and strengths in 1977 .
 This has been revised from time to time and the current is the 20th list (2017)
which has 433 medicines.
 India produced its National Essential Drugs List in 1996, and has revised it in
2011, and now in 20 15 with the title "National List of Essential Medicines".

Essential Medicines 18th edition (1977)-
WHO Model List
Examples of some essential medicine
1.Antibacterials: azithromycin, ciprofloxacin
2. Inhalational medicines - halothane , isoflurane ( General anesthetics)
3. Injectable medicines : ketamine, propofol ( General anesthetics )
4. Medicines For Pain: acetylsalicylic acid, ibuprofen, paracetamol
5. Antituberculosis medicines: ethambutol, isoniazid, pyrazinamide, rifampicin

Drug Nomenclature
A drug has at least three types of names:
1. Chemical name (IUPAC) or scientific name- Based on molecular structure
of the drug. E.g. 2-acetoxybenzoic acid/ acetyl salicylic acid
2. Generic name-
Given by FDA/WHO while approved, the short hand version of chemical
name. Recommended in RX. E.g. Aspirin
3. Brand name-
It is the name assigned by the manufacturer(s) and is his property or trade mark.
One drug may have multiple proprietary names, E.g. Jusprin®, disprin

Routes of Drug administration
Is the path by which a drug, fluid, poison or other
substance is brought into contact with the body

Commonly Used Routes of Drug Administration

ROUTES OF DRUG ADMINISTRATION
 Most drugs can be administered by a variety of routes.
 The choice of appropriate route in a given situation depends both on drug as
well as patient related factors.
 Routes can be broadly divided into those for -
(a) Local action
(b) Systemic action

LOCAL ROUTES
 These routes can only be used for localized organs/ tissue at approachable
sites and for drugs whose systemic absorption from these sites is minimal
or absent.
 Thus, high concentrations are attained at the desired site without exposing
the rest of the body.
 Systemic side effects or toxicity are consequently absent or minimal.
E.g. glyceryl trinitrate (GTN) applied on the skin as ointment or transdermal
patch for angina pectoris ( chest pain)

The local routes are :
1. Topical
 This refers to external application of the drug to the surface for localized
action.
 It is often more convenient as well as reassuring to the patient.
 Drugs can be efficiently delivered to the localized lesions on skin, nasal
mucosa, eyes, ear canal, anal canal or vagina in the form of lotion, ointment,
cream, powder, rinse, drops, spray, suppositories or pesseries.

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2 . Deeper tissues
 Certain deep areas can be approached by using a syringe and needle, but the
drug should be in such a form that systemic absorption is slow.
 e.g. intra-articular injection (hydrocortisone acetate in knee joint),
intrathecal injection (lidocaine)
3. Arterial supply
 Close intra-arterial injection is used for contrast media in angiography.
Example: gadolinium contraxt used for MRI , Iodinated contraxt used for CT
scan , angiography

SYSTEMIC ROUTES
 Systemic administration is a route of administration of medication, nutrition
or other substance into the circulatory system so that the entire body is
affected.
 Administration can take place via enteral administration or parenteral
administration.
Systemic Routes include oral, sublingual, transdermal, nasal, inhalational,
rectal and other parenteral routes (intravenous, intramuscular, intradermal
and subcutaneous)

Enteral Route:
Oral route is safer and economical but several drugs are not effective by this
route because of high first pass metabolism in the liver and intestinal wall
(e.g. nitrates, lignocaine, propanolol, pethidine).

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Advantages: -
 Convenient - portable, safe, no pain, can be self-administered.
 Cheap - no need to sterilize (but must be hygienic of course)
 Variety of dosage forms available - fast release tablets, capsules, enteric
coated, layered tablets, slow release, suspensions, mixtures
 Convenient for repeated and prolonged use.

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Disadvantages: -
1.Sometimes inefficient :- high dose or low solubility drugs may suffer poor
availability, only part of the dose may be absorbed.
First-pass effect :-
 Drugs absorbed orally are transported to the general circulation via the liver.
 Thus drugs which are extensively metabolized will be metabolized in the liver
during absorption.
 e.g. the propranolol oral dose is somewhat higher than the IV, the same is true
for morphine

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2. Food :-
 Food and G-I motility can effect drug absorption.
 Often patient instructions include a direction to take with food or take on
an empty stomach.
 Absorption is slower with food for tetracyclines and penicillins, etc
3. Unconscious patient :- Patient must be able to swallow solid dosage
forms. Liquids may be given by tube

 1. Sublingual route
 Avoids first pass metabolism, can be used in emergencies, can be self
administered and also after getting the desired action, rest of the drug can be
spitted.
 Drugs like nitroglycerine (AP), isosorbide dinitrate (AP), clonidine (HBP) etc.
can be administered by sublingual route.

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ADVANTAGES
 Economical
 Quick termination
 First-pass avoided
 Drug absorption is quick
 Can be self administered
DISADVANTAGES
 Unpalatable & bitter drugs
 Irritation of oral mucosa
 Large quantities not given
 Few drugs are absorbed

2. Rectal route
Certain irritant and unpleasant drugs can be put into rectum as suppositories or
retention enema for systemic effect.
Example : enema used for childrens for bowel movement
ADVANTAGES DISADVANTAGES
Used in children Inconvenient
Little or no first pass effect Absorption is slow and erratic
Used in vomiting/unconsciuos Irritation or inflammation of rectum mucosa

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3. Inhalational route :
 Inhalation Volatile liquids and gases are given by inhalation for systemic
action, e.g. general anaesthetics – Nitric oxide, Halothane.
 The drugs administered by this route include drugs for asthma (e.g.,
salbutamol)

4. IV, IM ,SUBCUTENOUS

Parentral :
 Conventionally, parenteral refers to administration by injection which
takes the drug directly into the tissue fluid or blood without having to
cross the enteral mucosa.

Time of onset
 Intravenous 30-60 seconds
 Intraosseous 30-60 seconds
 Endotracheal 2-3 minutes
 Inhalation 2-3 minutes
 Sublingual 3-5 minutes
 Intramuscular 10-20 minutes
 Subcutaneous 15-30 minutes
 Rectal 5-30 minutes
 Ingestion 30-90 minutes
 Transdermal (topical) variable (minutes to hours)

Questions

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Great God, Medi-Caps, All the attendees

Introduction to general Pharmacology

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