1. PHARMACOLOGY
Pharmacon – Drug Logos- study /disclosure in
Science that deals with the study of drugs and their
interaction with the living system.

2. DEFINITIONS
 DRUG: “ A drug is 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 recipient”
 PHARMACOKINETICS: What the body does to the drug.
 PHARMACODYNAMICS: What the drug does to the body.

3. Contd…
THERAPEUTICS: deals with the use of drugs in the
prevention and treatment of disease.
PHARMACY : It is the science of identification,
compounding and dispensing of drugs. It also includes
collection, isolation, purification, synthesis and
standardization of medical substances ,

4. Contd….
CHEMOTHERAPY: It is the use of chemicals for the
treatment of infections. The term now also include the use of
chemical compounds to treat malignancies.
TOXICOLOGY : It deals with the adverse effects of drugs
and also the study of poisons. That is, detection, prevention
and treatment of poisonings.

5. NATURE OF DRUGS

6. All drugs are chemical in nature with simple and complex molecules.
Depends on various factors such as
❑ Physical properties
❑ Chemical properties
❑ Drug size
❑ Drug shape

7. SOURCES OF DRUGS
Natural Synthetic

8. Natural sources
Plants : oldest sources of drugs. Eg: Morphine, quinine
✓ Alkalloids {morphine, atropine, nicotine}
✓ Glycosides {digoxin, gentamicin}
✓ Oils
Animals: from animal parts/animal products. Eg : insulin, heparin
Minerals {Iron salts, Calcium salts, Lithium carbonate}

9. Contd..
 Microorganisms: Antibacterial agents are obtained from bacteria and
fungi.
Eg: pencillin, cephalosporins.
 Human {growth hormone, immunoglobulin from blood}

10. Synthetic sources
Obtained by cell cultures, recombinant DNA
technology, hybridoma techniques
Eg: quinolones, omeprazole

11. DOSAGE FORMS

12.  SOLID DOSAGE FORMS
 LIQUID DOSAGE FORMS
 SEMISOLID DOSAGE FORMS
 INHALATIONS

13. SOLID DOSAGE FORMS
 POWDERS: the drug is in dry and finely pulverized state
 TABLETS: The drug is powdered or granulated , mixed with binding agents and other
excipients and compressed and moulded into discoid, oblong or other shapes suitable for
swallowing.
❑ Chewable tablets
❑ Dispersible tablets
❑ Sublingual tablets
❑ Enteric coated tablets
❑ Sustained/extended release tablets
❑ Controlled release tablets

14.  PILLS: These are archaic dosage forms in which the drug powder is
mixed with honey/syrup to make sticky mass.
 CAPSULES: These are water soluble cylindrical containers made of
gelatin which are filled with powdered or liquid medicament.
 LOZENGES : These are tablet like bodies of various shapes containing
the drug along with a suitable gum, sweetening and flavouring agents.
 SUPPOSITORIES: These are conical bullet shaped dosage forms for
insertion into the anal canal, in which drug mixed with a mouldable firm
base that melts at body temperature and releases contained drug.

15. LIQUID DOSAGE FORMS
 Aqueous solutions : they contain the drug dissolved in water, and may
be meant for oral, topical or parenteral administration.
 Suspensions: These are dispersions of insoluble drugs in water with the
help of a suspending agent.
 Elixirs : these are hydroalcoholic solutions of drugs, usually sweetened
with syrups and flavoured by fruit extracts.
 Drops: these are relatively more concentrated solutions of medicaments
meant for oral ingestion or external applications to eye, nose or ear
canal.

16.  Lotions : These are solutions, suspensions or emulsions meant for external
applications to skin without rubbing.
 Injections: These are sterile solutions or suspensions in aqueous or oily
medium for subcutaneous or intramuscular administration.
SEMISOLID DOSAGE FORMS
 Ointments: these are greasy semisolid preparations meant for external
application to skin
 Pastes: these are non greasy preparations of thick consistency containing
hydrophilic adhesive powders.

17.  Gels: the medicament is incorporated in a viscous colloidal
solution of gelatin or similar material and is usually dispensed
in collapsible tubes.
INHALATIONS
• Drugs which are gases or volatile liquids can be administered
by inhalation carried into air or oxygen with the help of a
mouth piece, face mask, hood or endotracheal tube.

18. ROUTES OF ADMINISTRATION
LOCAL
SYSTEMIC

19.  Systemic route
The drug administered through systemic routes is intended to be absorbed
into the blood stream and distributed over including the site of action,
through circulation
❑ Oral
❑ Sublingual or buccal
❑ Rectal
❑ Nasal
❑ Cutaneous
❑ Inhalation
❑ Parenteral
Transmucous

20.  LOCAL ROUTES
These routes can only be used for localized lesions at accessible sites and for
drugs whose systemic absorption from these sites is minimal or absent.
❑ Topical
❑ Deeper tissues
❑ Arterial supply

21. ENTERAL ROUTE {oral ingestion}
 Most common, oldest and safest routes drug administration
Advantages
• Safest route
• Most convenient
• Most economical
• Non invasive route
Disadvantages
 Onset of action is slower as absorption needs time
 Irritation to GI tract
 Irregular absorption
 Cannot given to unconscious and uncooperative patients

22. Sublingual
 The tablet or pellet containing the drug placed under the tongue or crushed in the mouth
and spread over the buccal mucosa.
 Only lipid soluble and nonirritant drugs can be administered
 Absorption is relatively rapid
Eg: Glyceril trinitrate, buprenorphine
Rectal
 Certain unpleasant and irritant drugs can be put into rectum as suppositories or retention
enema for systemic effect.
 Useful for patient with continuous vomiting or unconscious
 It is rather inconvenient and embarrassing
 Absorption is slower, irregular and often unpredictable
 Rectal inflammation may occur due to irritant drugs
Eg: diazepam, indomethacin, paracetamol

23. Cutaneous
 Highly lipid soluble drugs can be applied for the skin for slow and prolonged absorption
 The drug can be incorporated in an ointment and applied over the specified area of skin.
Transdermal therapeutic system {TTS} : These are the devices in the form of adhesive patches of
various shapes and sizes which deliver the contained drug at a constant rate into systemic circulation .
For different drugs, TTS have been designed to last for 1-3 days. They provide smooth plasma
concentrations of the drug without fluctuations, minimize interindividual variations and side effects,
patient complaints is better. It is expensive.
Inhalation
 Volatile liquids and gases are given by inhalaltion for systemic action eg: general anesthetics.
 Absorption is rapid. Controlled administration is possible with moment ot moment adjustment.

24. Nasal
The mucous membrane of the nose can readily absorb many drugs . Eg: only certain drugs like
GnRH agonist, calcitonin
Parenteral
 Administration by injection which takes the drug directly into the tissue fluid or blood without
having to cross the enteral mucosa.
 Drug action is faster and surer
 It can be employed in unconscious, uncooperative or vomiting patients
 No chances of interferences by food or digestive juices.
Disadvantages
 Preparation has to be sterilized and is costlier
 Technique is invasive and painful.
 Assistance of another person is needed

25. 1. Subcutaneous route
 Dermojet
 Pellet implantation
 Sialistic and biodegradable implants
2. Intramuscular
3. Intravenous
4. Intradermal
Role of nurse

26. PHARMACOKINETICS
DRUG PLASMA
Site of
action
Tissue stores
Excretion
Metabolism

27. ABSORPTION
 Passage of drug from the site of administration into circulation
Factors influencing absorption
 Disintegration and dissolution time
 Formulation
 Particle size
 Lipid solubility
 Ionisation and pH
 Area and vascularity of absorbing surface
 Gastrointestinal motility
 Presence of food
 Metabolism
 Diseases

28. DISTRIBUTION
After drug reaches the systemic circulation, it gets distributed to various
tissues. It should cross several barriers before reaching the site of action.
 Plasma protein binding
 Tissue binding
 Blood brain barrier
 Placental barrier

29. METABOLISM
 Metabolism or biotransformation is the process of biochemical alteration of
the drug in the body.
 Body treats most drugs as foreign substances and tries to inactivate and
eliminate them by various biochemical reactions.

30. EXCRETION
 Drugs are excreted from the body after being converted to water
soluble metabolites while some are directly eliminated without
metabolism.
❑ Renal excretion
❑ Faecal and biliary excretion
❑ Pulmonary excretion
❑ Other routes

31. DRUG INTERACTION
 Drug interaction is the alteration in the duration or the magnitude of the
pharmacological effects of one drug by another drug.
❖ Invitro interaction
❖ Invivo interaction

32. PHARMACODYNAMICS

33. Drugs act by
Stimulation
Depression
Irritation
Replacement
Antiinfective or cytotoxic action
Modification of the immune status

34. RECEPTOR
 Defined as macromolecule or binding site located on the surface
or inside the effector cells that serves to recognize the signal
molecule or drug to initiate the response to it, but itself has no
other function.
Some terms which describe the drug interaction
 Agonist
 Inverse agonist
 Antagonist
 Partial agonist
 Ligand

35. Nature of receptor
❖ Regulatory molecules
❖ Mostly proteins, nucleic acids.
❖ Molecular cloning has also helped to obtain the receptor protein in larger quantity
to study its structure and properties and in subclassifying receptors.
❖ Each receptor has a well defined common structural motif while individual
receptors differ in details of sequencing length of intra/extracellular loops.
❖ Clinically useful drugs act upon physiological receptors which mediate response
to transmitters, hormones, antacids.
❖ Receptors which have no endogenous mediator or ligand is called orphan receptor.

36. DRUG SYNERGISM
When action of one drug is enhanced or facilitated by another drug , the combination is synergestic.
Total effect of combination is greater than the sum of their independent effects called drug
synergism.
Eg: levodopa+carbidopa
ANTAGONISM
One drug opposing or inhibiting the action of another drug
It may be 2 types
 Chemical antagonism: 2 substances interact chemically to result in inactivation of the effect
 Physiological antagonism: two drugs act at different sites to produce opposing effects

37. Antagonism at receptor level
❑ Reversible antagonism
❑ Irreversible antagonism
❑ Non competitive

38. TOLERANCE
Requirement of higher dose of a drug to produce a given response. It may be natural
and acquired
Natural
The species is inherently less sensitive to drug. Certain individuals may hypo
responders or hyper responders to certain drugs.
Acquired
Occurs by repeated use of a drug in an individual who was initially responsive. An
uninterrupted presence of the drug in the body favours development of tolerance.

39. Cross tolerance
Development of tolerance to pharmacologically related drugs.
Tachyphylaxis
Rapid development of tolerance. When some drugs are administered repeatedly at short
intervals, tolerance develops rapidly and is known as tachyphylaxis or acute tolerance.
Eg: amphetamine, tyramine.
Mechanisms of tolerance
1. Incompletely understood
2. Drug disposition tolerance
3. Cellular tolerance

40. ADVERSE DRUG REACTIONS
“Any response to a drug that is noxious and unintended and that occurs at
doses used in man for prophylaxis , diagnosis or therapy” – WHO
Side effects
Unwanted effects of drug that are extensions of pharmacological effects
and are seen with therapeutic dose of the drug.
Toxic effects
Seen with higher doses of drug and can be serious