Pharmacology-1 4th sem (Introduction)

1. Prepared by-Shagufta Farooqui
Assistant Professor
General Introductionto Pharmacology

2. Introduction
Pharmakon-Drug
Logos- study
Pharmacology is the study of drug.
Drugs are chemicals that Produce Therapeutically useful effects.
They modify the functions of living organism, and are generally given to prevent,
diagnosis,or cure disease processes.
Pharmacology is defined as a science of drugs. It includes knowledge about the
sources of drugs, their absorption, distribution, metabolism and excretion, their
mode of action, and their toxicity .

3. Introduction
Pharmacology has the following major subdivision-
1.
• Pharmacognosy-(Greek, gnosis,Knowledge)
• Study of source of drugs derived from plants and animals and of the physical and chemical properties of
such substances
2.
• Pharmacy-Is the study of preparation ,compounding and dispensing of medicines. It is the sciences and art
of preparing drugs or drug combination in a suitable dosage form fit for administration to the patients.
3.
• Pharmacokinetics( Greek kinesis, movement)is the study of fate of drugs in the body ,right from the time
they(drug) enter the body until they, or their by products are eliminated from the body i.e the movement of
drugs in the body.(ADME)
4.
• Pharmacodynamics (Greek dynamics,Force) it is the experimental study of actions drug on the living
organism, including their mode of action
5.
• Therapeutics(Greek Therapeutike,medical practice) is the practical branch of medicine dealing with
science and art of medicine dealing with the science and art of the treatment of disease.
6.
• Pharmacotherapeutics(Greek Therapeia medical treatment) is the treatment of disease by means of drugs.
• It utilizes information on drugs obtained by phramcodynamic studies.
7.
• Chemothrapy(Paul Ehrlich) Deals with the use of drugs capable of inhibiting or destroying invading
microbes,parasites,or cancer cells,while having minimal effect on healthy living tissues

4. 1.
• Toxicology-(Greek toxikon, poison) is the science of poisons-their source,
chemical composition, action, tests for detection and antidotes.
• It forms a major art of forensic and environmental medicine.
2.
• Clinical Toxicology- Deals with detection, diagnosis and treatment of
poisoning.
3.
• Pharmacogentics-is a relatively new field ,and deals with the study of
genetically determined variations in drug response
4.
• Clinical Pharmacology- is the division which deals with the pharmacologic
effects of drugs . It provide information about the usefulness, potency and
toxicity of new drug in humans.

5. Historical Landmarks of Pharmacology
Third Phase
Scientific phase, understanding of disease
mechanism provided a scientific basis for using
drug
Isolation of pure drugs from plant(e.g morphine
from opium)
Second Phase
Simple External preparation such as cool mud
or soothing leaf
Egyptian prescriptions called for castor oil,
opium and other drugs that are still used today
First Phase
Noxious plant and animal preparation were
administered to a patients
Magic Charm for treating disease

6. Current phase-
The goal of pharmacology is to understand the mechanism by which drug interact with
biologic systems to enable the rational use of effective agents in the diagnosis and
treatment of disease.
The success of pharmacology in this task has led to an explosion of new drug
development. Isolation of insulin for diabetes, the discovery of antimicrobial and
antineoplastic drugs.

7. Scope of Pharmacology
Pharmacology Scope
Neuropharmacology, Gastrointestinal pharmacology, Respiratory Pharmacology,
immuno pharmacology, cardiovascucular pharmacology
Pharmacogentics
Pharmacogenomic
s
Pharmacoepidemio
logy
Pharmacoeconomi
cs
Biochemical
Pharmacology
Pharmcokinetics
Molecular
Pharmacology
Chemotherapy

8. Source and Nature of drugs
• Sulphonamides,Thi
azide diuretics,oral
antidiabetics
• Ferrous sulphate for
anemia,magnesium
trisilicate for
hyperacidity and
peptic ulcer
• e.g
• Insulin-extracted
from pork and beef
pancrease
• e.g
Quinine,morphine,e
phedrine and
digoxin
Plant
source
Animal
source
Synthetic
source
Mineral
Source

9. Nature of drugs
Alkaloi
ds
Gums
Tannin
s
Oils
Glycosi
des Resins
Antibi
otics

10. Alkaloids-(Alkali –like) are compound composed of carbon, hydrogen, nitorgen
and oxygen.
Bitter taste and are often poisonous hence given in small doses.
The name of an alkaloid end in “ine” e.g- caffeine, atropine and morphine.
Alkaloids are basic substances and combine with acid to form a salt
Both alkaloids and their salts are precipitated by tannic acid and oxidized by
potassium permagnate, hence these substances can be used as antidotes for
poisoning from alkaloids.
Glycosides-
These are ether like combinations of sugars with other organic substances found
in plants
Glycosides referred as glucoside if the sugar in combination is glucose.
e.g-Cardiac glycosides found in digitalis leaf.

11. Oils
The term oil is applied to a large number of liquids which are insoluble in water and
highly viscous. their greesy feel is the result of these properties.
Oils are of two types
1.Volatile oils
II. Fixed oils
1.Volatile oils are liquids that impart an aroma to a plant and are volatilized by
heat.
They evaporate and leave no greesy stain, because of their pleasant odour and taste
they are frequently used as a flavouring agents.
e.g-peppermint oil, clove oil, oil of wintergreen is almost pure methyl salicylate
used locally for relief of muscle and joint pains.
2.Fixed oils-are the glycerides of oleic acid, palmitic acid and stearic acid
Extracted mainly from seeds,occuring as a droplets or crystals
e.g-Olive oil,castor oil, peanut oil

12. 4.Tannins- They are non nitrogenous plant constituents, and have an astringent action
They are of two types-
1) Pyrogallol tannins- glycosides of glucose and occur in oak galls,
2) Pyrocatechol tannins-which are sugar-free derivatives of catechol and occur in
catechu and eucalyptus.
Tannins are used for treating burns and diarrhoea.
5.Gums -are exudates from plants. chemically they are polysaccharides and on
hydrolysis yield simple sugars. Upon addition of water some of them swell up and
form adhesive mucilaginous masses and some remain unchanged.
In hydrophilic (water loving) colloids and function as a bulk laxatives e.g agar,
psyllium seeds.
Tragacanth gum in the form of an emulsion is used for chapped skin.
Acacia is used as a suspending agent in making emulsions and mixtures like Bismuth-
Kaolin Mixture for Diarrhoea.

13. 6.Resins -Solid substances found in plants, and they are produced by oxidation and
polymerization of volatile oils. They are insoluble in water and soluble in alcohol, ether
and chloroform.
Resins are of many types-
1.Gum-resins(asafoetida)
2.Oleo-gum resins(myrrh)
3. Balsams(Benzoin,tolu,peru)
Balsams used to treat cough and bronchitis for their antiseptic and protective properties.
7.Antibiotics- They are chemical substances produced or derived from living cells which
have a lethal(bactericidal) or inhibitory (bactriostatic) action on micro-organisms.

14. Essential drugs concept
Essential medicines are the medicines that satisfy the priority health care needs of the
population
These are the medications to which people should have access at all times in sufficient
amounts.
WHO
Developed a list of
essential drug and
revised every two
years
1Priority to health
care needs of the
population with
1.Efficacy and
safety
2.Adequate amount
3. Appropriate
dosage forms

15. Route of drug Administration
Oral route
Parenteral Route
Nasal Route
Sublingual route
Rectal route

17. Intradermal
Subcutaneous
Interamascular
Intravenous
Intramedullary
Intrathecal
Parenteral route of drug Administration
Epidural
Intracardiac
Intra-Articular
Intramedullary
Intra-Arterial

20. Oral route of drug Administration
Advantages:
1. Safest and most economical
2. This route is the most convenient route of drug administration
3. Patients can take the prescribed medicines himself
4. There is no pain to the patient, this route is very convenient and economical
e.g-Tablets, capsules, mixtures, emulsions, suspensions.
Disadvantages:
1.The effect of drug taken by oral route is delayed
2. This is not an emergency route
3. The irritant drugs cannot be given through this route
4.This route cannot be used in case of unconscious and non-cooperative patients
5.Certain drugs cannot be given through this route as they are destroyed by gastric enzymes.
6.Objectional odour and taste
7.Damage or discoloration of teeth

21. Sublingual route of drug Administration
The tablets are placed under the tongue sucked.
Some drugs like isoprenaline and nitro-glycerine may be given by
placing them under the patients tongue, where they are retained until
dissolved and absorbed or the desired effect is produced.
Advantages:
Onset of action is quick
The overdose of drug is avoided
The drug is not destroyed by stomach enzyme, metabolic destruction
in the liver is prevented .
Patients must be instructed not to swallow the tablet and water should
not be taken immediately after the tablet to ensure proper sublingual or
buccal absorption.

22. Parenteral route of drug Administration
Parenteral route refers to any route other than gastrointestinal route (Enteral)
These routes are selected-
when the drug is poorly absorbed from the gut, or
Inactivated by digestive enzymes, or metabolized during its first passage through the liver
Or if the patient is unable to tolerate or take oral medications
Or if rapid effect is desired

23. Intradermal Route:
The drug is injected into the outer layer of the skin
The amount of drug is given in small quantity and absorption is slow
The medial surface of forearm is the site frequently used.
This test is mainly used for diagnostic test like shick test for diphtheria ,tuberculine test
Local anaesthetics are first injected intradermally and then further deeper injections are made.
Also used for allergic sensitization testing in patients.

24. Subcutaneous route:
The injection is made into loose subcutaneous tissue under the skin.
The common sites are upper arm, abdomen and front of thigh
The drug absorption is slower and the action is longer than IV or IM.
Drugs like adrenaline, morphine and insulin are usually administered subcutaneously

25. Intramuscular route:
The injections is given with the longer and heavier needle that penetrates the
subcutaneous tissues and the drug is deposited deep between the layers of the muscle
mass.
This route is suitable for administration of solutions or suspensions
Muscles are more vascular and less sensitive to than subcutaneous injection sites.
Absorption is faster and rapid
Small volume up to 3ml are injected into deltoid muscles.
Small or large volume are injected into gluteal mass underlying the upper and outer
quadrant of the left or right buttock. Drugs like sex hormones, corticosteroids, procaine
penicillin G.

26. Intravenous route:
When an immediate effect is desired
It may be introduced directly into a vein as an injection or infusion.
The cubital vein at the bend of elbow is selected or superior longitudinal sinus in
children may be selected
IV injection require small amount of solution referred as bolus, are given by
means of syringe
An infusion is the IV administration of larger amounts of fluid varying from 1 to
2 litres.
Infusion are mostly given-
to relieve tissue dehydration,
to restore depleted blood volume,
to dilute toxic substances in the blood and tissues,
to supply electrolytes, drugs and foods.

28. Intramedullary injection:
Also designated as bone marrow injection and the material is injected to the bone
marrow of the sternum or tibia. This route is used when the veins are not available,
specially in childrens.
Whole blood ,normal saline or glucose may be administered by this route.
Intra-arterial injection:
Needle is placed in an artery, through which an arterial blood sample may be
withdrawn for blood gas studies or a radio-opaque substance may be injected to
make arteries of the part visible on an X-ray film (Arteriography)
Certain cytotoxic drug may be perfuse through artery for treating specific areas.

29. Intra-thecal (Intra-spinal) injection:
Drug is injected into the subarachnoid space. Needles are inserted through the
vertebral interspinous spaces into the spinal fluid, by lumbar puncture
This route is used to produce intense action of drugs on cerebrospinal system
while treating infectious types of meningitis or to produce spinal anaesthesia
or for introduction of radio-opaque contrast media into the subarachnoid
spaces to visualize the spinal cord (myelography)

30. Epidural injection: By this method the drug is deposited through the vertebral
interspaces between the dura of the spinal cord and the periosteal linning of the spinal
canal
It is used to produce epidural nerve block by depositing the local anaesthetic solution in
the space where spinal nerves emerges from the dural membrane and enter the
intervertebral formina .

31. Intracardiac injection:
In some emergency conditions like sudden cardiac arrest during anaesthesia
,electrocution ,injection of adrenaline given directly into the heart may restart the heart
beat. The injection is given by a long needle in the left fourth intercostal space close to
the sternum.

32. Intra-articular injection:
The drug is injected into the joint spaces to attain the high local concentration within
inflamed joint, without much danger of systemic steroid toxicity