The document provides information about pharmacology and related topics. It discusses the definition of pharmacology as the study of drugs and their actions on the body. It also covers key concepts such as pharmacokinetics, pharmacodynamics, drug dosage forms, routes of administration, absorption, distribution, metabolism, excretion, and factors that influence drug response.

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PHARMACOLOGY

3. PHARMACOLOGY
Greek Word
Pharmacon Logos
Drug Science
Science of drugs- dealing with the study of
Desirable and Undesirable effects.

4. Pharmacology is the study of drugs
and their actions on the body

5. What is PHARMACOLOGY ?
Pharmacokinetics Pharmacodynamics
What the body does to drug What the drug does to body
Pharmacology
Pharmacotherapeutics Pharmacy
The study of the use of drugs Preparing suitable dosage forms
Toxicology

6. PHARMACO THERAPEUTICS
It is a branch of medicine
concerned with the cure of
disease or relief of symptoms
and induces drug treatment.

7. PHARMACY
It is the science of:
•Identification
•Selection
•Preservation
•Standardization
•Compounding, and
•Dispensing of medicinal substances

8. PHARMACOPOEIA
• It is an official code containing a selected
list of the established drugs and medicinal
preparations with descriptions of their
physical properties and tests for their
identity, purity and potency. e.g. IP, BP,
USP, etc.
IP: Indian Pharmacopoeia
BP: British Pharmacopoeia
USP: United states
Pharmacopoeia

9. DRUG
“ Drug is any substance or product that is used
or is intended to be used to modify
physiological systems or pathological states for
the benefit of the recipient .”

10. “Poisons in small doses are the
best medicines; and useful
medicines in too large doses are
poisonous”
William Withering 1789

11. DRUG NAMES
• Chemical…states its chemical composition
and molecular structure.
• Generic…usually suggested by the
manufacturer.
• Official…as listed in the Pharmacopoeia.
(I.P., B.P., U.S.P.)
• Brand…the trade or proprietary name.

12. DRUG NAMES
1,4 benzodiazepine analog
Chemical Name
Generic Name Alprazolam
Official Name Alprazolam, USP
Brand Name Alprax®

13. THE NATURE AND SOURCES OF DRUGS
• Mineral • Liquid paraffin, magnesium
sulfate, etc
• Animal • Insulin, Thyroid, etc.
• Plant • Morphine, Quinine etc
• Synthetic • Aspirin, Sulfonamides, etc.
• Micro-organisms • Penicillin & other antibiotics.
• Drugs produced • Human insulin, human growth,
by genetic hormone etc.
engineering

14. DRUG DEVELOPMENT PROCESS
Chemistry
Synthesis & Purification
Formulation
Animal Pharmacology
Animal Toxicity (Short / Long term)
Studies in Humans
Drug Authorities
Market

15. DRUG DEVELOPMENT PROCESS

16. DOSE Vs DOSAGE
• Dose: The quantity of drug administered
at one time
• 500mg of Paracetamol
• Dosage: The amount of the drug that
should be given over time
• 500 mg Paracetamol TID for 3 days

17. DRUG DOSAGE FORMS
Tablets
Aerosol Capsule
Suspension Injection
Cream Infusion
Solution

18. ROUTES OF DRUG ADMINISTRATION
How the drug is given
Enteral Parenteral Topical
(injectable)
1. Oral 1. Intravenous 1. Intranasal
2. Sublingual 2. Intramuscular 2. Inhalation
3. Rectal 3. Subcutaneous 3. Intravaginal

19. IV, IM & SC Route of
Administration

20. ADVANTAGES AND DISADVANTAGES OF
ORAL, IV, IM AND SC ADMINISTRATION
SAFETY
High Oral > SC > IM > IV Low
CONVENIENCE
High Oral > SC > IM > IV Low
COST
High IV > IM > SC > ORAL Low

21. ADVANTAGES AND DISADVANTAGES OF
ORAL, IV, IM AND SC ADMINISTRATION
BIOAVAILABILITY
High and Reliable IV > IM = SC > ORAL Low &/or Variable
ONSET OF ACTION
Immediate IV > IM > SC > Oral Delayed
PATIENT COMPLIANCE
High Oral > SC > IM > IV Low

22. PHARMACOKINETICS
• The study of what the body does to the drug
• It is the study of absorption, distribution,
metabolism and excretion (ADME) of drugs
• “Fate of drug”

23. PHARMACOKINETICS
•Absorption
How the drug is moved into blood stream from the site of
administration ?
• Distribution
How much drug is moved to various body tissues / organs ?
Depends on blood flow through tissue
• Metabolism
How the drug is altered – broken down ?
• Excretion
How much of the drug is removed from the body ?

24. ABSORPTION
BIOLOGICAL BARRIER
Site of Administration Vascular System
DRUG

25. Drug Absorption of Various Dosage Forms
Oral Preparations
Liquids, elixirs, syrups Fastest
Suspension solutions 
Powders 
Capsules 
Tablets 
Coated tablets 
Enteric-coated tablets Slowest

26. IV Route
What would the graph of blood level against time
look like?
Blood
level
Time

27. ORAL Route
What would the graph of blood level against time look like?
Blood
level
Time

28. What is happening in these two phases?
? ?
Blood
level
Time

29. Absorption Metabolism
and and
Distribution Excretion
Blood
level
Time

30. BIOAVAILABILITY
• Bioavailability is a fraction of administered
dose of a drug that reaches the systemic
circulation in the unchanged form.
• Bioavailability of IV route : 100 %

31. BIOAVAILABILITY
Destroyed Not Destroyed Destroyed
in gut absorbed by gut wall by liver
to
Dose systemic
circulation

32. BIOAVAILABILITY
Factors influencing bioavailability
• Dosage forms
• Chemical form
• Dissolution & Absorption of drug
• Route of administration
• Presence of food/drugs in GI tract
• First pass effect
• Extent of drug metabolism before reaching
systemic circulation

33. MSC
MEC

35. Concept of Critical Threshold
• MEC (Minimum Effective Concentration):
The minimum level of drug concentration
needed for the desired therapeutic effect to be
present.
• MSC (Maximum Safe Concentration): The
maximum level of drug concentration above
which toxic effects occurs.
OR
• MTC (Minimum Toxic Concentration):
The minimum level of drug concentration
that produces toxic effects.

36. •Maximal Effect: Greatest response that can
be produced by a drug, above which no
further response can be created (sometimes
called “peak effect”)
•Onset: How long before a drug is able to
exert a therapeutic effect
•Duration: How long a drug effect lasts

37. DRUG HALF-LIFE (t1/2 )
• Half life is the time required to reduce the
plasma concentration to 50% of its original
value
• Will determine dosing requirements / how
long a drug will remain in the body
• Used in determining dosing interval
• Goal - Plateau

38. DRUG HALF-LIFE (t1/2 )
110
100
90
Concentration (m g/L)
80
70
60
50
40
30
20
10
0
0 1 2 3 4 5 6 7 8 9
Tim e (hours)
Half-life is the time taken for the concentration of drug in blood to fall by a half
Half-life is 2 hrs

39. DRUG HALF-LIFE (t1/2 )
• 1t 1/2 - 50 % drug is eliminated
• 2 t1/2 - 50+25 (75 %) drug is eliminated
• 3 t1/2 - 50+25 +12.5 (87.5 %) drug is eliminated
• 4 t1/2 - 50+25 +12.5+6.25 (93.7 %) drug is
eliminated
Thus, nearly complete drug elimination occurs in 4-5
half lives.

40. DRUG HALF-LIFE (t1/2 )
50
25
12.5
6.25
3.12
1.56

41. Cmax & Tmax
Cmax
not art nec no C
Tmax
Time
•Cmax - Maximum conc. achieved in the blood
i
•Tmax - Time taken to attain maximum conc.

42. AUC (Area Under Curve)
AUC
• AUC is the area under the plot of plasma
concentration of drug against time after drug
administration.

43. DISTRIBUTION
Distribution is a branch of pharmacokinetics
which describes the reversible transfer of drug
from one location to another within the body.

44. DISTRIBUTION
Locus of Tissue
action reservoirs
“receptors”
Bound Free Bound Free
Systemic
circulation
Absorption Free drug Excretion
Excretion
Bound drug Metabolites
Biotransformation

45. Plasma- Protein Binding
• Many drugs bound to circulating plasma
proteins such as albumin, lipoproteins,
glycoprotein, globulins etc.
• Free form
• Pharmacologically active
• Bound form
• Pharmacologically inactive
Receptor Site
Protein-bound drug
Free Drug

46. Protein Binding
• Drugs can bind with proteins
• Acts as temporary store of drug
• Prolongs it’s action
• Cause prolonged low level of drugs
• Slowly released from bound reservoir
• Delays metabolism
• Delays excretion
• Decreases its entry into CNS

47. Dosing
• Dosing Interval - How often the drug
should be given
• Loading dose – Which puts the plasma
concentration in the therapeutic range
• Maintenance dose - Routine smaller doses
to maintain the steady state (Plateau)

48. METABOLISM
 Metabolism = change / biotransformation
 The conversion from one chemical form to another
Site of drug biotransformation
• Liver - cytochrome P450 pathways OR microsomal
P450 pathways are used to metabolize most
agents
• Enzymatic alteration of drug structure
 Effect of metabolism
 80% of drugs become inactive
 Inactive drug becomes active: Prodrug
 Some drugs do not get metabolised at all

49. METABOLISM
 Majority of drugs are metabolized in liver by
enzymes – Cytochrome P 450
 Drugs may induce (activate) or inhibit these
enzymes
Drug – Drug interactions

50. First Pass Metabolism
The first-pass metabolism (also known as first-pass
effect or presystemic metabolism) is a phenomenon of
drug metabolism whereby the concentration of a drug
is greatly reduced before it reaches the systemic
circulation.

51. First Pass Metabolism
Hepatic
Swallowed Digestive Rest of
portal Liver
Drug system the body
system

52. First Pass Metabolism
Systems that affect the first pass effect of the drug,
• Enzymes of the gastro intestinal lumen
• Gut wall enzyme
• Bacterial enzymes
• Hepatic enzymes

53. First Pass Metabolism
Effect of first pass metabolism
Part of administered dose made inactive
↓ bioavailability
Drug converted into its active form
• Nitroglycerin when given orally
• Totally inactivated in the liver
• 100% first pass effect
• Always given sublingually

54. Prodrug
 Administered in an inactive form
 After administration converted into their active form
 usually in liver
 Designed to improve bioavailability
 Examples
 Enalapril – Enalaprilate
 Ramipril - Ramiprilate

55. METABOLISM
Factors affecting metabolism :
1. Age – Children / Elderly
2. Disease condition – e.g. Liver disease
3. Induction of drug metabolizing enzymes
4. First-pass effect – Nitroglycerin
5. Competition between drugs
6. Genetics
7. Environment e.g. Smoking

56. Excretion
Drugs &/or its metabolites are irreversibly
eliminated from the body
• Elimination of the drug
• Unchanged (Parent form)
• Metabolites
• Routes of excretion
• Kidneys – Urine
• GIT – Stools
• Skin - Perspiration
• Eyes - Tears

57. PHARMACODYNAMICS
• The study of what the drug does to the body
• It is the quantitative study of the biological and
therapeutic effects of drugs.

58. PHARMACODYNAMICS
Drug actions:
• The cellular processes involved in the drug
and cell interaction
Drug effect:
• The physiologic reaction of the body to the
drug

59. PHARMACODYNAMICS
Onset
• The time it takes for the drug to elicit a
therapeutic response
Peak
• The time it takes for a drug to reach its
maximum therapeutic response
Duration
• The time a drug concentration is sufficient
to elicit therapeutic response

60. Four targets of drug action on cells
• Receptors
• Ach receptors / Epinephrine receptors
• Ion Channels
•Voltage gated Na+ / K+ / Ca++
• Enzymes
•Cyclooxygenase / Acetylcholine esterase
• Carriers
•Na+/ K+ pump / Proton Pump

61. Receptors
• Specific macromolecular components of
the cell which when binds with ligand
produces positive or negative biological
response
• Situated - on the surface / inside the cell

62. • Affinity: Inherent ability of the drug to bind with the
receptor
• Efficacy (Intrinsic activity): Inherent ability of the
drug to induce a physiological response
• Potency: An expression of the activity of the drug, in
terms of the concentration or amount needed to
produce a defined effect

64. What drug can do?
All that drugs can do is,
• Mimic the physiological activity of the
body’s own molecules
• Block the physiological activity of the
body’s own molecules

65. Drug at Receptor
• Agonist : It activates a receptor to produce an
effect similar to that of the physiological signal
molecule
• Antagonist : It prevents the action of an agonist
on a receptor but does not have any effect of its
own
• Partial agonist : It activates a receptor to produce
sub maximal effect but antagonizes the action of
full agonist.

66. Agonist v/s Antagonist
• Drug + Receptor  EFFECT
• Drug + Receptor  Maximum Effect
• Drug = complete or full agonist
• Drug + Receptor  Less than maximal effect
• Drug = partial agonist
• Drug + Receptor  Block effect
• Drug = Antagonist

67. Effects of combination of drug
• Addition 1+1=2
• Response elicited by combined drugs is equal to
the combined response of the individual drugs
• Synergism 1+1=3
• Two drugs with the same effect are given
together and produce a response greater than
the sum of their individual responses

68. Effects of combination of drug
• Potentiation 0+1=2
• A drug which has no effect enhances the effect
of a second drug
• Antagonism 1+1=0
• Drug inhibits the effect of another drug.
Usually, the antagonist has no inherent activity

69. Factors affecting drug response
• Pharmacological
•Dose & Route of administration
•Duration of treatment
•Co-administration of other drugs
• Individual
•Age & Weight
•Gender
•Pathology
•Diet

70. Indication & Contraindication
• Indication:
A clinical circumstance indicating that the
use of a particular intervention would be
appropriate
• Contraindication:
Any condition which renders a particular
line of treatment improper or undesirable.

71. Adverse drug reaction
What does the term adverse reaction refer to?
A. A life-threatening response to a drug
B. A drug-induced allergy
C. A harmful, noxious, unintended & undesirable
response to a drug
D. An unpredictable response to a drug

72. Adverse drug reactions
 Side effect
 Toxicity – overdose
 Allergic reaction
 Physical dependence
 Carcinogenic effect

73. Adverse drug reactions: Definitions
• Side Effect
• Unavoidable unintended pharmacodynamic effects that occur
at a therapeutic dose
• Dryness of mouth with Atropine
• Toxic effects
• Result of excessive pharmacological action of the drug due
to overdosage or prolonged use
• Hepatic necrosis from paracetamol overdosage
• Drug intolerance
• Toxic effects of a drug in an individual at therapeutic doses
• Vomiting with a single dose of salicylate
• Drug tolerance
• Decreased response to the same amount of drug after repeated
administration

74. Adverse drug reactions: Definitions
• Cross Tolerance
• Tolerance for a drug that develops after administration of a
different drug
• Tachyphylaxis
• Rapidly occurring tolerance to a drug.
• Cumulative effect
• Increased effectiveness when a drug is given in several doses.
• Drug dependence
• The patient becomes accustomed to the drug’s presence in his
body.

75. Adverse drug reactions: Definitions
• Idiosyncrasy
• Drug effect unique to an individual,
A. a toxic reaction
B. an allergic reaction
C. a reaction peculiar to the patient
D. an anaphylactic reaction
• Drug allergy
• Immunologically mediated reaction
• Symptoms unrelated to pharmacodynamic profile of drug
• Independent of dosage
E.g. Penicillin
• Drug withdrawal symptoms
• Functional disturbances induced by a drug Persists even after
offending drug has been withdrawn

76. Adverse drug reactions: Definitions
• Teratogenecity – induce birth defect
• Capacity of a drug to cause foetal abnormalities
• Thalidomide
• Mutagenic Effect
• Mutagenesis involves alteration of the genotype by
modification of the DNA
• Mutation is carried to the next generations
• Photosensitivity
• Cutaneous reaction resulting from drug induced sensitization
of the skin to UV radiation
• Quinolones

77. Drug Safety–Therapeutic Window
• Therapeutic Index (or Window) measures “how safe a
drug is” or “Margin of safety”
• High therapeutic index = safe
• Low therapeutic index = not so safe
The larger the ratio, the safer the drug

78. Therapeutic Index/Ratio
• Therapeutic Index/Ratio: Is the ratio between lethal
dose (LD) and effective dose (ED) this is useful
measure of safety and efficacy of any drug.
• Lethal dose: The amount of the drug which kills
subjects when it is administered is called lethal dose
• Effective dose: The amount of the drug which
removes sign & symptoms of subjects when it is
administered

79. PLACEBO:
Drug devoid of intrinsic pharmacological activity and
it works by psychological means.
USES : ??????

80. PHASES OF CLINICAL
DEVELOPMENT
• Phase 1: Clinical pharmacology
• Phase 2: Clinical investigation
• Phase 3: Formal therapeutic trials
• Phase 4: Post licensing (marketing)
studies

81. Pregnancy Considerations
• Increased maternal HR, CO and blood volume
• May affect absorption, distribution, effectiveness
• Drugs may cross placenta
• Drugs may cross into breast milk
• Tertatogens

82. Pregnancy Categories
• A: controlled studies in pregnancy (<1 %).
• B: animal studies show no risk; Inadequate
human data.
• C: animal studies show risk, inadequate
human data.
• D: human data show risk, benefit may
outweigh risk.
• X: animal or human data positive for risk. Use
unwarranted.

83. Pediatric Considerations
∀ ⇓ Oral absorption
• Thinner skin (⇑ topical absorption)
∀ ⇓ Plasma protein concentration
∀⇑ Free protein-bound drug availability
∀ ⇑ Extracellular fluid in neonate
• Altered metabolic rates
∀ ⇓ Elimination/metabolism
• BSA/weight based dosing important!

84. Geriatric Considerations
∀ ⇓ Oral absorption
∀ ⇓ Plasma protein concentration
∀ ⇓ Muscle mass, ⇑ body fat
∀ ⇓ Liver/renal function
• Multiple drugs
• Multiple diseases

85. FUNDAMENTALS OF PHARMACOLOGY
• The rational pharmacological treatment of
any patient requires adequate knowledge
about :
 The disease process,
 Pharmacodynamic properties of the
drug(s) selected, and
 The individual’s handling of the drug(s)
[pharmacokinetics].

86. OPTIMUM DRUG CONCENTRATION
• The concentration must not be too low,
nor too high.
• In the former case, therapeutic failure
may occur, while in the later, adverse
effects may prove troublesome to the
patient.

87. FUNDAMENTALS OF PHARMACOLOGY
• Drugs act by affecting biochemical or
physiological process in the body. Most
drugs act at specific receptors.
• The action of a drug is characterized by
two variables:
 The magnitude of the response and
 The concentration required to produce the
response.

88. FUNDAMENTALS OF PHARMACOLOGY
• A specific drug acts only at one receptor
but may produce multiple effects due to the
location of the receptor in various organs.
• A selective drug acts on one receptor in a
particular tissue at concentrations that
produce little effect on the receptor in other
organs.
• Most drugs have multiple actions and it is
usually preferable to use more specific or
more selective agents

89. THANK
YOU