This document provides an introduction to pharmacology. It defines pharmacology as the study of drugs and their interactions with living systems. Drugs are substances used for diagnosis, prevention or treatment of disease. Drugs can come from natural sources like plants, animals and microorganisms, or be synthesized. Common routes of drug administration include oral, sublingual, buccal, rectal, intravenous, intramuscular and topical. Pharmacokinetics describes what the body does to drugs through processes of absorption, distribution, metabolism and excretion. Pharmacodynamics describes what drugs do to the body through their mechanisms and sites of action. Factors like dosage, age, weight and interactions can influence drug effects.

1. 1. INTRODUCTION
TO
PHARMACOLOGY
DR. SAROJ K. SUWAL

2. CONTENTS
• Terminology
• Source of drugs
• routes of drug administrations
• Pharmacokinetics, pharmacodynamic and
principle

3. DEFINITION? PHARMACOLOGY
• Is science that deals with the study
of drugs and their interaction with
the living systems.
• Pharmacology is derived from
Greek
• pharmacon → drug
• logos → study.

4. DRUG:
•is a substance used in the
• diagnosis,
• prevention or treatment of disease.

5. SOURCE OF DRUGS
•Natural
•Plant, Animal, Microoranisms,
Minerals
•Synthetic
•Semi synthetic
•synthetic

6. Source of drugs

7. • Human and animals:
• epinephrine,
• insulin
• adrenocorticotropic
hormone

8. Plant Source
• Leaf,
• steam,
• root,
• flower,
• seeds

15. • Pharmacologic Classification
• Similar Characteristics
• Similar Chemical Make up
• examples: Penicillin's, Beta Blockers
Drug Basic Classifications
• Therapeutic Classification
• Used for similar effect
• May not have similar chemical
make up
• Examples: Antihypertensives,
Antibiotics

16. ROUTE OF DRUG ADMINISTRATIONS

17. ROUTE OF ADMINISTRATIONS
• ORAL
• SUBLINGUAL
• BUCCAL
• RECTAL
• TRANSLINGUAL
• SUBCUTANEOUS
• INTRAMUSCULAR
• INTRADERMAL
• INTRAVENOUS
• INHALATIONAL
• TOPICAL

19. the most common Route
tablets, syrups, capsules
• ORAL-GI Route
• BUCCAL ROUTE
• SUBLINGUAL ROUTE
ORAL route

20. ADVANTAGES:
 Least expensive
 Easily Available
 most convenient route for most clients.
 Safe, does not break the skin.
 Conscious, able to swallow.

21. Disadvantages:
• Inappropriate for patient with nausea and vomiting.
• may have unpleasant taste.
• May cause irritation to gastro intestinal tract.
• discolor teeth and tongue
• can be aspirated

22. 2. SUBLINGUAL
drug placed under the tongue, where it dissolved.
Advantage:
• Same as oral plus
• Drug may administered for local effect.
• Drug rapidly absorbed into blood stream.
• More potent than oral.

23. Disadvantage:
• If swallowed drug may be inactive.
• Drug must remain under the tongue until
dissolved.
• May differ with the taste

24. BUCCAL ROUTE

25. Rectal:
• Used in children
• Little or no first pass effect (ext haemorrhoidal vein)
• Used in vomiting or unconscious
• Higher concentrations rapidly achieved
Translingual:
• on the tongue.

26. THROUGH SKIN
•Intramuscular
•Subcutaneous
•Intravenous,
•Intradermal

27. into in the muscle.
Sites: Gluteal muscle,deltoid, thigh muscle,
Advantage:
• Pain from irritating drugs is minimized.
• Can administer large volume of drug.
• Drug rapidly absorbed.
Disadvantage:
• breaks skin barrier.
Intramuscular (IM):

30. Subcutaneous (SC):
• hypodermic into subcutaneous tissue, just below
the skin.
• Advantage:
• onset drug action faster than oral.
• Disadvantage:
• Must involve sterile technique because breaks skin barrier.
• More expensive than oral.
• Can administer only small doses.
• Slower than intramuscular injection.
• Some drug can irritate tissue and can cause INTENESE pain.

32. Intradermal (ID):
is the administrating of a drug into the dermal layer of the skin just
beneath the epidermis, usually small amount of liquid is used for
example 0.1ml.
• Advantage:
• absorption is slow (this advantage test for allergy).
• Disadvantage:
❖amount of drug administered must be small.
❖Breaks skin barrier

33. 8. Intravenous (IV):
•allow injection of drugs and another substance
directly into bloodstream through the vein.
9. Inhalation:
• is apply to drugs directly onto lungs.

35. 10. Topical Route
1. Skin (including transdermal patches)
2. Eyes
3. Ears
4. Nose
5. Lungs (inhalation)

36. • Pharmacokinetics
and
• Pharmacodynamics

38. PHARMACOKINETICS:
what the body does the drug
• kinesis ➔ movement
• is the study of the ADME

39. PHARMACOKINETICS
(THE PRINCIPLE OF ADME)
• Absorption
• Distribution
• Metabolism
• Excretion

40. ABSORPTION:
• May be via several routes
• Oral (mucosa,sublinguial)
• GI tract(intestines) – In
aqueous form
• Skin (eg.fentanyl patch)
movement of a drug into the bloodstream. from the site
of administration

41. ABSORPTION BY
1. Active transport
2. Passive Transport
• diffusion ( passive, facilitated diffusion)
• Endocytosis
• Exocytosis

42. BIOAVAILABILITY OF DRUGS
proportion of a drug which enters the
circulation when introduced into the body
to have an active effect.
IV route→ Bioavailability 100 % or 1
other route → less then 100 % or 1

43. DISTRIBUTION
• drugs leave the
bloodstream and
distribute into the
interstitial and
intracellular fluids
• Factors
• Depends on tissue permeability
• Depends on tissue perfusion
• Depends on amount of blood flow
• pH can affect

44. METABOLISM
• drug bio-transformed by the
metabolism in liver, and other
tissues( lungs, kidney,skin etc)
• most of drugs are metabolized
in Liver
• First pass metabolism or effect

45. FIRST PASS EFFECT
• Metabolism of drug in the gut
wall or portal circulation before
reaching systemic circulation
• so the amount reaching system
circulation is less than the
amount absorbed

47. EXCRETION -ALSO REFERRED TO AS CLEARANCE
• Relies mostly on KIDNEYS-
urine
• Skin-sweat,
• GI-stool ,
• nose
• Lungs

49. HALF-LIFE OF A DRUG
• is defined as the time taken for the
concentration of the drug in the plasma
• the time taken for the plasma
concentration of a drug to reduce to
half(50%) its original value
Elimination of a drug varies from person to person due to
factors like age, weight, other medications taken, or other
medical conditions present, also kidney function, liver function
etc.Therefore half-life is used as a guide or an estimate of how

51. MOST DRUGS ELIMINATION BY
• first order kinetics
• zero order kinetics

52. FIRST ORDER KINETICS

53. ZERO ORDER KINETICS

54. PHARMACODYANAMICS
•what the drug does the
body
•Also called drug actions
• Dynamics ➔Mechanics
•is the study of
• the effect of the drugs on the body
and their mechanism of action

55. PHARMACO DYANAMICS( DRUG ACTIONS)
Drugs
enter the
human
stimulate
• enzymes
• transporter proteins
cause body
To
react in a
specific way.
• receptors,
• ion channels,
act on
result
`

56. MECHANISMS OF DRUG ACTION
• Drugs work by altering normal cell and
tissue function.
• Specific groups of drugs have affinity
(attractive force) for specific target
cells, known as receptors.
Drugs
Binds to Receptor
Phamacological effect
• Agonist action
• Antagonist action

57. DRUG ACTION
• Agonist and Antagonist actions
• Agonists - they stimulate and activate the receptors
• Antagonists - they stop the agonists from stimulating
the receptors

59. THERAPEUTIC INDEX
• the ratio of the dose that produces toxicity to
the dose that produces a clinically desired
response in the population of the individuals
TI=TD50/ED50
Where ,
• TD50=the drug that produces toxic effect in
effect
• ED50=the drug that produces a therapeutic
effect
This is a measure of a drug’s safety
• A large number = a wide margin of safety
• A small number = a small margin of safety

60. DRUG ACTION
•DESIRED effect
• ( PCM decreased temperature)
•undesirable effect
• known as side effects

61. ADVERSE REACTIONS
• Allergic Reactions
• Hives
• Itching
• Edema
• Anaphylactic reaction
• Respiratory distress
• Cardiovascular collapse

62. RISKS WITH DRUGS
• Carcinogenicity
• ability of a drug to cause living cells to mutate and
become cancerous
• Teratogen
• drug that induces birth defects

63. FACTORS INFLUENCING DRUG ACTION
• Age --?overdosing and side effects
• Body Weight
• Metabolic Rate
• Illness
• Psychological Aspects
• Placebo effect
• Tolerance/Dependence
• Cumulative effect

64. DRUG INTERACTIONS
• Drugs can “mix” or interact with other
things
• Drugs
• Foods,Juices
• Disease

65. DRUG INTERACTION
• can cause
• decrease action
• increase action
• adverse effect

66. DRUG – DRUG INTERACTION
• two or more drugs can have
interactions

67. TYPES OF DRUG INTERACTIONS
• In terms of efficacy, several types of interactions
between medications:
• cumulative,
• additive,
• synergistic, and
• antagonistic.

68. Response
Time
Cumulative Effects
Drug A
Drug B
The condition in which repeated administration of a drug
may produce effects that are more pronounced than those
produced by the first dose.

69. Response
Hi
Lo
Time
A B
Additive Effects
A + B
The effect of two chemicals is equal to the sum of the effect of
the two chemicals taken separately,
Codeine+ Paracetamol
Addition
( increased analgesic effect)

70. Response
Time
A B
A + B
Synergistic Effects
The effect of two chemicals taken together is greater than the
sum of their separate effect at the same doses, e.g., alcohol and
other drugs
Aspirin+ Warfarin
leads to
(excessive
bleeding)
Clavulanic acid +
Amoxicillin
(increased
antibiotic effect)

71. Response
Hi
Lo
Time
A B
A + B
Antagonistic Effects
The effect of two chemicals taken together is less than
the sum of their separate effect at the same doses
Phenobarbital + Warfarin
Antagonism (less effect)

72. DRUG –FOOD INTERACTIONS
• Benzodiazepines + grapefruit→ Inhabit enzymes involved in drug
metabolism
• Benzodiazepines + grapefruit →Inhabit enzymes
involved in drug metabolism
• Digoxin + Oatmeal →Decreased adsorption of drug
• Aspirin + Milk →Upset stomach
• Acetaminophen + Alcohol →Liver damage

73. DRUG –DISEASE INTERACTIONS
• Nasal decongestants+ Hypertension→ Increased blood
pressure
• NSAID’S+ Asthmatic patients →Air way obstruction
• Minoxidil+ Heart failure →Fluid rentetion
• Nicotine + high blood pressure →Increased heart rate
• Beta blockers+ Heart failure →Worsen asthma
• Metformin + Heart failure →Increased lactate level

74. • Thank you