Lecture 1- Pharmacology

1. Introduction to
Pharmacology
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Shivankan Kakkar, MD
Assistant Professor,
Department of Pharmacology,
SMS Medical College Hospital,
Jaipur

2. Introduction
(Definitions and Sources of Drugs)
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■ Pharmacology: It is the science that deals with the effects of drugs on
living systems.
■ Drug: World Health Organization (WHO) defines drug as ‘any
substance or product that is used or intended to be used to modify or
explore physiological systems or pathological states for the benefit of
the recipient’.

3. ■ Pharmacokinetics: It means the movement of drug within the body; it
includes the processes of absorption (A), distribution (D), metabolism
(M) and excretion (E). It means ‘what the body does to the drug’.
■ Pharmacodynamics: It is the study of drugs – their mechanism of
action, pharmacological actions and their adverse effects. It covers all
the aspects relating to ‘what the drug does to the body’.
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4. ■ Pharmacy: It is the branch of science that deals with the
preparation, preservation, standardization, compounding,
dispensing and proper utilization of drugs.
■ Therapeutics: It is the aspect of medicine concerned with the
treatment of diseases.
■ Chemotherapy: It deals with treatment of infectious
diseases/cancer with chemical compounds that cause relatively
selective damage to the infecting organism/ cancer cells.
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5. ■ Toxicology: It is the study of poisons, their actions, detection,
prevention and treatment of poisoning.
■ Clinical pharmacology: It is the systematic study of a drug in man,
both in healthy volunteers and in patients. It includes the evaluation
of pharmacokinetic and pharmacodynamic data, safety, efficacy and
adverse effects of a drug bycomparative clinical trials.
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6. ■ Essential medicines: According to WHO, essential medicines are ‘those
that satisfy the healthcare needs of majority of the population’. They
should be of assured quality, available at all times, in adequate quantities
and in appropriate dosage forms. They should be selected with regard to
disease prevalence in a country, evidence on safety and efficacy, and
comparative cost-effectiveness. The examples are iron and folic acid
preparations for anaemia of pregnancy, antitubercular drugs like
isoniazid, rifampicin, pyrazinamide, ethambutol, etc.
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7. ■ Orphan drugs: Drugs that are used for diagnosis, treatment or
prevention ofrare diseases. The expenses incurred during the
development, manufacture and marketing of drug cannot be recovered
by the pharmaceutical company from selling the drug, e.g. digoxin
antibody (for digoxin toxicity), fomepizole (for methyl alcohol poisoning),
etc.
■ Over-the-counter drugs (OTC drugs, nonprescription drugs): These drugs
can be sold to a patient without the need for a doctor’s prescription,
e.g. paracetamol, antacids, etc. 7

8. ■ Prescription drugs: These are drugs which can be obtained only upon
producing the prescription of a registered medical practitioner, e.g.
antibiotics, antipsychotics, etc.
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9. SOURCES OF DRUG INFORMATION
Pharmacopoeia: It is a book which contains a list of established and
officially approved drugs with description of their physical and chemical
characteristics and tests for their identification, purity, methods of storage,
etc. Some of the pharmacopoeias are the Indian Pharmaco- poeia (IP), the
British Pharmacopoeia (BP), and the United States Pharmacopoeia (USP).
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10. Other sources of drug information are National Formulary (NF),
Martindale – the Extra Pharmacopoeia, Physician’s Desk Reference
(PDR), American Medical Associa- tion Drug Evaluation, textbooks
and journals of pharmacology and therapeutics, drug bulletins,
databases like Micromedex, Medline, Cochrane Library, etc.
Information can also be obtained from pharmaceutical companies
through their medical representa- tives, meetings and drug
advertisements in journals.
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11. Formulary: It provides information about the available drugs in a
country – their use, dose, dosage forms, adverse effects,
contraindications, precautions, warnings and guidance on selecting
the right drug for a range of conditions.
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12. DRUG NOMENCLATURE
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Drugs usually have three types of names, which are as follows:
1. Chemical name: It denotes the chemical structure of a drug, e.g.
acetylsalicylic acid is the chemical name of aspirin and N-acetyl-p-
aminophenol is of paracetamol. It is not suitable for use in a
prescription.

13. 2. Nonproprietary name: It is assigned by a competent scientific
body/authority,e.g. the United States Adopted Name (USAN) council. WHO
along with its member countries select and recommend the International
Nonproprietary Name (INN) for a drug. So, it is uniform throughout the
world and denotes the active pharmaceutical ingredient. Few older drugs
have more than one nonpro- prietary name, e.g. the opioid, pethidine and
meperidine. The INN is commonly used as generic name. Ideally, generic
names should be used in prescriptions because it is economical and
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14. generally uniform all over the world than the branded counterparts.
Examples are aspirin and paracetamol are generic names.
3. Proprietary name (brand name): It is given by the drug manufacturers.
Brand names are
short and easy to recall. Drugs sold under brand name are expensive as
compared to their generic version. A drug usually has many brand names –
it may have different names within a country and in different countries.
Brand names can also be used in prescriptions. Disprin is a brand name of
aspirin; Crocin forparacetamol. 14

15. Chemical name Nonproprietary
name
Proprietary name/brand
name
Acetylsalicylic acid Aspirin • Disprin
• Ecosprin
N-acetyl-p- aminophenol
(Acetaminophen)
Paracetamol • Crocin
• Metacin
• Tylenol
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16. SOURCES OF DRUGS
They are natural, semisynthetic and synthetic. Natural sources are plants,
animals, minerals, microorganisms, etc. Semisynthetic drugs are obtained
from natural sources and are later chemically modified. Synthetic drugs
are produced artificially.
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17. The different sources of drugs:
1. Plants:
a. Alkaloids are nitrogen containing compounds, e.g.
morphine, atropine, quinine, reserpine, ephedrine.
b. Glycosides contain sugar group in combination with nonsugar
through ether linkage,
e.g. digoxin, digitoxin.
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18. c. Volatile oils have aroma. They are useful for relieving pain (clove
oil), as carminative
(eucalyptus oil), flavouring agent (peppermint oil), etc.
d. Resins are sticky organic compounds obtained from plants as
exudate, e.g. tincture benzoin (antiseptic).
2. Animals: Insulin, heparin, antisera.
3. Minerals: Ferrous sulphate, magnesium sulphate.
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19. 4. Microorganisms: Penicillin G, streptomycin, griseofulvin
(antimicrobial agents),
streptokinase (fibrinolytic).
5. Semisynthetic: Hydromorphone, hydrocodone.
6. Synthetic: Most of the drugs used today are synthetic, e.g. aspirin,
paracetamol.
Drugs are also produced by genetic engineering (DNA recombinant
technology),e.g. human insulin, human growth hormone and hepatitis
B vaccine.
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