Pharmacology is the study of how chemicals interact with living organisms and affect biochemical functions, primarily concerning drug safety and efficacy. The two main areas are pharmacokinetics, which describes what the body does to a drug, and pharmacodynamics, which describes what a drug does to the body. Drugs are administered through various routes and undergo absorption, distribution to tissues, metabolism in the liver, and elimination from the body, mostly through urine or feces.

1. What is pharmacology
 It is the study of the interactions that occurs
between a living organism and chemical that
affect normal or abnormal biochemical
functions.
 It is mainly concerned with safety and efficacy
of drugs .
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2. Two main areas of pharmacology are
 Pharmacokinetics.
 Pharmacodynamics.
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3. Pharmacokinetics
What the body does to the drug.
PHARMACODYNAMICS
What the drug does to the body
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4. Fundamental Pathways of Drug Movement
& Modification in the Body
 DRUG AT THE SITE OF
ADMINISTRATION
Drug in
plasma
1 . ABSORPTION
(INPUT)
2. DISTRIBUTION
3. METABOLISM
4. ELIMINATION
(OUTPUT)
Drug & metabolites in urine,
feces, or bile
drug in tissues
metabolites in tissues
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6. Routes of Drug Administration
Determined primarily by the properties of the
drug
There are two major routes of drug administration
1. Enteral
2. Parenteral
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7. Routes of Drug Administration
1. ENTERAL
A. ORAL
B. SUBLINGUAL
C. RECTAL
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8. ENTERAL routes
A. ORAL
B. SUBLINGUAL
C. RECTAL
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9. PARENTERAL routes
IV /
intravascular
SC /
subcutaneou
s
IM /
intramuscular
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10. Parenteral
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11. 3. Others
 Inhalation
 Intranasal
 Intrathecal, intraventricular
 Topical
 Transdermal
Routes of Drug Administration
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12. Routes of Drug Administration
3. Others
A. Inhalation
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13. Other
Intranasal
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14. Others
c. Intrathecal, intraventricular
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15. Others
d. Topical
e. Transdermal
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16. III. ABSORPTION OF
DRUGS
Transport of Drug from the GIT
1. Passive Diffusion
2. Active Transport
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17. IV. Bioavailability
Refers to the fraction of an administered drug
that reaches the systemic circulation
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18. V. Drug Distribution
Affected by the following factors:
- 1. Blood Flow.
- 2. Capillary permeability.
- 3. Binding of Drugs to proteins.
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19. Binding of Drugs to Plasma Proteins
Bound drugs are pharmacologically
INACTIVE,
only the FREE, UNBOUND drug can act
on target sites in the tissues
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20. Reactions of Drug
Metabolism
 The kidney cannot
efficiently eliminate
lipophilic drugs ,
therefore lipid soluble
agents must 1st be
metabolized in the liver
using 2 general sets of
reactions
PHASE I
PHASE II
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21. Phase I
 Converts lipophilic molecules into more polar
molecules
 Phase I metabolism may increase, decrease, or
leave unaltered the drug’s pharmacologic
activity.
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22. Phase II
 Renders the metabolites INACTIVE and more
water soluble
 The highly polar drug conjugates may then be
excreted by the kidney or bile
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23. DRUG ELIMINATION
 Removal of a drug from the body may occur via
a number of routes, the most important being
the kidney or urine
 Other routes:
- bile, intestine, lung, milk,
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24. DRUG ELIMINATION
 Drugs that have been made water soluble
in the liver are often readily excreted in the
kidneys.
 Kidney dysfunction can lead to toxic levels
of the drug in the body because the drug
cannot be excreted.
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