4. Specific Learning Objectives of PH1.1
At the end of this theory session the phase II MBBS
student will be able to:
• Define terminology pharmacology,
• Define terminology pharmacotherapeutics,
• Describe the principles of pharmacology,
• Describe the principles of pharmacotherapeutics.
• Define Drug and various terminologies relevant in
Pharmacology course,
• Summarize expansion of pharmacology.
5. Pharmacology
Definition:
“It is the branch of science that deals with
interaction of exogenously administered
chemical molecules in the living system”.
Pharmakon – Drug, Logos - Study
6. What is a DRUG ?
• Drogue (French) – a dry herb
• Definition: WHO (1966)
– “Drug is any substance or product that is used
or intended to be used to modify or explore
a physiological system or a pathological
state for the benefit of the recipient”.
8. What is a Pharmacotherapeutics?
• Definition:
“Application of pharmacological
information together with the knowledge
of the disease for its diagnosis, prevention
and cure”.
9. • Describe the principles of pharmacology,
and / or
• Describe the principles of
pharmacotherapeutics.
10. To explain / understand easily about the principles
of pharmacology and the principles of
pharmacotherapeutics:-
• Any exogenously administered molecules
effects the physiological or pathological
states, either due to:
Living Body’s Factors:
Means
What the body does to
the drug?
Exogenously administered
drug factors:
Means
What the drug does to the
body?
12. Pharmacokinetics
• Kinesis (Greek) – movement
• Definition:
– This refers to “the movement of the drug in
the body, and the alterations of the drug by
the body through:
»Absorption
»Distribution
»Metabolism
»Excretion”.
13. Pharmacodynamics
• Dynamics (Greek) – power
Definition:
– “This refers to “the physiological and
biochemical effects of drugs and their
mechanisms of action at:
macromolecular
subcellular
organ system level”.
14. PHARMACOGENETICS :
Study of Genetic influences on responses to drugs.
• Examples :
(a) Fast Acetylation of INH is in Eskimos, Japanese.
(b) Slow Acetylation of INH is in Jews, Scandinavians,
North African Caucasians. the study of the
cost-effectiveness of drug treatments”.
(c) Primaquine induced hemolysis in G6PD deficient
individuals, occur in ~ 10% of black males in USA & in
some coloured Caucasian ethnic groups.
(d) Atypical pseudocholinesterase results in prolonged
succinylcholine apnoea.
15. • Pharmacotherapeutics:
– Application of pharmacological information
together with the knowledge of the disease
for its prevention and cure.
• Chemotherapy:
– Treatment of systemic infections /
malignancies with specific drugs that have
selective toxicity for the infecting organism
/ malignant cell, with no / minimal effects on
the host cell.
16. PHARMACOGENOMICS :
Use of genetic information to guide the choice of
drug therapy.
It is a branch of pharmacology, which deals with the study of heritable
variations in genes that determine the drug response in human beings,
microbes and tumors and explores the methods to use these
variations to predict the response of drug in a patient. This genome
based approach help to develop more specific (target) and safer drug
”. Exam.: Gefitinib is highly effective in curing lung cancer but only in
those patients who have mutations in the tyrosine kinase receptor
(10% of the cases), which is targeted action of this drug.
This branch overlaps pharmacogenetics.
17. Definition : Chronopharmacology
• “Study of drug effects which is based on
biological timing as well as its effects upon
circadian rhythm is called Chronopharmacology”.
• Examples :
(a) Peak effects of histamine-induced skin reaction to
intradermal injection or airway reactivity common at
midnight.
(b) Peak Ach-induced bronchial reaction occur mainly at
noon.
(c) Alteration in plasma glucose & growth hormone
circadian rhythm by insulin.
18. Definition : Placebo
• Latin = I please,
• “it is an inactive substance or preparation which
is used for its nonspecific, psychological or
psychophysiological effect on a patient, on
symptoms or on an illness.”
• Examples :
(a) Vitamin B1, B6 & B12 are used as placebo in absence of
vitamin deficiency.
Note: * Placebo may have some physiological effect, e.g.
release of endogenous opioids in the brain, b/k
naloxone can overcome placebo-induced analgesia.
* Placebo used mainly as a control in experimental studies.
19. PHARMACOEPIDEMIOLOGY :
Study of drug effects at the population level.
PHARMACOECONOMICS :
Branch of health economics, aims to quantify in
economic terms, the cost and benefit of drugs
used therapeutically.
BIOTECHNOLOGY:
Use of recombinant DNA Technology for
manufacturing therapeutic proteins, Diagnostics,
Genotyping etc.
20. Divisions in Pharmacology
• Clinical Pharmacy
– Evaluation of various formulations of drugs.
• Clinical Pharmacology
– Evaluation of drug action in humans.
• Experimental Pharmacology:
– Evaluation of drug action in animals.
• Communication Pharmacology:
- Evaluation of communication skills regarding the
drug’s require information deliver to the patient /
pharmacist.
21. Definition : Pharmacy
• “It is the art & science of compounding &
dispensing drugs or preparing suitable
dosage forms for administration of drugs in
man & animals. It includes collection,
identification, purification, isolation,
synthesis, standardization & quality control
of medicinal substances”.
22.
23. Definition : Toxicology
• “It is study of poisonous effect of drugs &
other chemicals (house-hold, environmental
pollutant, industrial, agricultural, homicidal)
with emphasis on detection, prevention &
treatment of poisonings”.
24. Describe the principles of pharmacology,
and / or
Describe the principles of pharmacotherapeutics.
1) Pharmacokinetics –
a. Absorption,
b. Bioavailability,
c. Storage,
d. Distribution,
e. Volume of Distribution,
f. Storage, Binding capacity
g. Metabolism,
h. Elimination.
i. Drug Dosing: Standard Dose, Regulated
Dose, Target Level Dose, Titrated Dose, etc.
2) Pharmacodynamics –
a. Ion channel mediated,
b. G Protein coupled protein
Receptors,
c. Tyrosine Protein Kinase
Receptor,
d. Nuclear Receptor
mediated.
e. Non-enzymatic mediated
action.
25. Describe the principles of pharmacology,
and / or
Describe the principles of pharmacotherapeutics.
3) Fixed Dose Combinations
(FDC) of Drugs:
Advantages: –
Better patience compliance,
synergistic drugs more effective,
more than two component of
therapeutic effects add up –
amlodipine + Atenolol,
Side effects counteract among
two drugs,
Multi-drugs therapy reduces drug
resistance.
Disadvantages:-
Unwanted FDC increases cost of the
therapy,
FDC difficult to individualize the dose,
Time course is different but in FDC it is
not applicable,
Individual component alter renal /
hepatic function differently,
Individual component Side effect difficult
to overcome,
Contraindication to one component
(allergy etc.) contraindicates the whole
component.
Confusion of therapeutic aims & false
sense of superiority of two drugs over
one is fostered.
26. Describe the principles of pharmacology,
and / or
Describe the principles of pharmacotherapeutics.
4) Factors modifying Drug Action:
i. Body Size:
• Average built person require standard
dose,
• Exceptionally obese, lean, and for children
need BSA to calculate accurate dose.
ii. Age:
• Premature newborn, mature newborn,
Infant, children: GFR is low, tubular
transport is immature and hepatic enzymes
inadequately developed.
• Elderly- Renal function, hepatic functions
declined progressively.
iii. Sex:
Females have smaller body size, thus
lower side dose range required than
average male.
Digoxin increases mortality in female
CHF more than male of CHF.
Clonidine, methyldopa, β-blockers,
diuretics interfere with sexual function in
males but not in females.
Ketoconazole, metoclopramide
chlorpromazine, digitalis, cause
gynaecomastia in male.
Ketoconazole cause loss of libido in
male but not in female.
27. Describe the principles of pharmacology,
and / or
Describe the principles of pharmacotherapeutics.
4) Factors modifying Drug Action:
During Pregnancy:
GIT motility is reduced – delay absorption,
Vd increased due to expansion of plasma
and ECF.
Risk of acidic drugs toxicity increases b/k
fall in albumin.
Risk of basic drug toxicity decreases.
Polar drugs eliminate faster – b/k increase
Renal blood flow.
Many drugs metabolized faster – b/k
hepatic microsomal enzymes undergo
induction.
iv. Species and Race:
• Rabbit resistant to atropine.
• Rat , mice are resistant to digitalis.
• Rat more sensitive to curare than Cat.
Blacks require higher and Mongols
require lower concentrations of atropine
and ephedrine to dilate their pupil.
β – blockers are less effective as
antihypertensive in Afro-Caribbeans.
Widespread use of chloramphenicol in
India and Hong Kong between 1950 –
1980, relatively few cases of aplastic
anaemia reported than the west.
v. Genetics:
Pharmacogenetics-
Pharmacogenomics
vi. Route of Drug Administration:
• governs speed and intensity of drug
response.
28. Describe the principles of pharmacology,
and / or
Describe the principles of pharmacotherapeutics.
4) Factors modifying Drug Action:
vii. Environmental factors and Time
of administration of drug:
• Rabbit resistant to atropine.
• Rat , mice are resistant to digitalis.
• Rat more sensitive to curare than Cat.
viii. Psychological Factors:
• Efficacy of drug can be affected by the
patient’s belief, attitudes and expectations.
• Placebo:
• Nocebo:
ix. Pathological states:
• GIT Diseases:
• Hepatic diseases:
Kidney Diseases:
CHF:
Thyroid Diseases:
X. Other Drug:
XI. Cumulation:
XII. Tolerance: Natural, Acquired, Cross
Tolerance.
• Acquired Tolerance:
• Cross Tolerance:
XIII. Tachyphylaxis:
XIV. Drug Resistance:
5) Pharmaceutical Factors: Particle
size, Salt form, Crystal form, Water of Hydration,
Nature of Excipients & Adjuvants, Degree of
Ionization.
29. A. Pharmaceutical Factors:
1. Particle size_
While ↓ing the particle size SURFACE AREA of
the particle will ↑d, thus absorption will be faster,
so bioavailability will be more.
Example: Microfined p/ps of Aspirin,
spironolactone, Griseofulvin, Digoxin, etc.
30. A. Pharmaceutical Factors:
2. Salt form
As a rule, salt of weakly acidic drugs are highly
soluble in water.
Free acidic drug is precipitated from these salts
in a microcrystalline form which has faster
dissolution rate and enhanced bioavailability.
Example: Tolbutamide sodium, Phenytoin sodium have
better bioavailability than tolbutamide & Phenytoin (as
free drugs).
31. A. Pharmaceutical Factors:
3. Crystal form
Amorphous form of the p/ps, like
chloramphenicol palmitate, amorphous
novobiocin have faster dissolution rate &
better bioavailability compared to their
crystalline forms.
32. A. Pharmaceutical Factors:
4. Water of Hydration
Many drugs can associate with water to
produce crystalline forms called the
HYDRATES.
The anhydrous forms of caffeine,
theophylline & ampicillin have faster
dissolution rate & better bioavailability
compared to their hydrous forms of these
drugs.
33. A. Pharmaceutical Factors:
5. Nature of Excipients & Adjuvants
These are pharmaceutical inert substances
(e.g., starch, lactose, calcium sulfate, gum,
polysorbate-80) which are added to the
formulation as a filling material to ↑d bulk of
the p/ps.
34. A. Pharmaceutical Factors:
6. Degree of Ionization
Nonionized lipid soluble drugs are better
absorbed, while
Strongly acidic or basic drugs or highly
ionized drugs show reduced bioavailability
from GIT, e.g. streptomycin, neostigmine, Ach
& its analogues, d-Tubocurarine.
35. B. Pharmacological & Physiological
Factors:
1. Gastric Emptying & GI. Motility,
2. Food & Other substances,
3. First – Pass Effect,
4. Drug – Drug Interactions,
5. Gastrointestinal diseases,
6. Pharmacogenetic Factors,
7. In addition, All other factors which
influence absorption of drugs.
37. Overall goal of the Pharmacology
The broad goal of the teaching of
pharmacology to the undergraduate
students in Pharmacology is to inculcate a
rational and scientific basis of
therapeutics.
38. A) KNOWLEDGE :
(1)Describe the pharmacokinetics and pharmacodynamics of essential
and commonly used drugs.
(2) List of indications, contraindications, interactions, and adverse
reactions of commonly used drugs:
(3) Indicate the use of appropriate drug in a particular disease with
consideration to its cost efficacy and safety for Individual needs
(5) Mass therapy under national health programmes.
(6) Describe the pharmacokinetic basis, clinical presentations.,
diagnosis and management of common poisonings.
39. (7) List the drug’s addiction and recommend the management.
(8) Classify environmental and occupational pollutants and state the
management issues.
(9) Indicate causation in prescription of drugs in special medical situations such
as pregnancy, lactation, infancy and old age.
(10) Integrate the concept of rational drug therapy in clinical pharmacology.
(11) State the principles underlying the concept of “Essential Drugs”.
(12) Evaluate the ethics and modalities in the development and introduction of
new drugs.
40. B) SKILLS :
(1) Prescribe drugs for common ailments.
(2) Recognize adverse reactions and interactions of commonly used drugs.
(3) Observe experiments designed for study of effects of drugs, bio-assay and
interpretation of the experimental data.
(4) Scan information on common pharmaceutical preparations and critically
evaluate drug formulations.
C) INTEGRATION :
• Practical knowledge of use of drugs in clinical practice will be acquired through
integrated teaching with clinical departments and pre-clinical departments.
