Pharmacology is the study of chemicals, or drugs, on living tissues and how they can diagnose, treat, cure, or prevent disease. Drugs originate from four main sources - plants, animals, herbals, and minerals. Pharmacokinetics refers to what the body does to drugs, including absorption, distribution, and elimination, while pharmacodynamics refers to what drugs do to the body and their effects. Drugs can be administered through several routes including orally, intravenously, intramuscularly, and other methods, each with their own advantages and disadvantages for drug delivery and absorption.

3. Pharmacology is the study of chemicals—drugs—on living tissues
and how those chemicals help diagnose, treat, cure, and prevent
disease or correct the patho-physiology of living tissues.
The term pharmacology is derived from two Greek words: pharmakon,
the Greek word for drugs, and logos, the Greek word for science.

4. If you ask an adult where drugs come from and he
answers from the drug store.
Drugs can be purchased from a drug store, but the
origins are from one of four sources.
The Source of Drugs

Plants

Animals

Herbals

Minerals

5. 
Drug: Any substance that brings about a change
in biologic function through its chemical action.
Alters state in the body

6. Drugs
Drugs have three effects: these are
The therapeutic effect to fight or prevent a disease;
A side effect that isn’t harmful; and
An adverse effect that is harmful to a varying degree.

7. DOSAGE
Plasma
Concentration
EFFECTS
SITE OF
ACTION
Pharmacokinetic
Pharmacodynamics

8. PHARMACOKINETICS
Pharmacokinetics is the study of the drug concentration
during absorption, distribution, and elimination of a drug in
the patient.
Small intestine where the membrane of the intestine absorbs
drug particles passing them into the bloodstream, where
plasma circulates the particles, throughout the body.

9. Pharmacodynamics is a drug’s effect on the
physiology of the cell and the mechanism that
causes the pharmaceutical response. that a drug
delivers.
There are two types of effects.
The primary effect is the reason for which the drug
is administered.
The secondary effect is a side effect that may or
may not be desirable.

10. Pharmacodynamics

11. Pharm
acokinetic
Pharmacodynamics

12. Bioavailability is a measurement of % of a drug, reaches the
systemic circulation
Only drugs administered intravenously have a 100%
bioavailability because they are directly injected into
the vein.
Bioavailability
Typically, between 20% and 40%
of drugs that are administered
orally reach the blood stream

13. Bioavailability

14. Routes of Drug
Administration

15. 
The possible routes of drug
entry into the body may be
divided into two classes:

Enteral

Parenteral

16. Enteral Routes

Enteral - drug placed directly in the GI tract:

Sublingual - placed under the tongue

Oral - swallowing

Rectum - Absorption through the rectum

17. Sublingual/Buccal
Some drugs are taken as smaller tablets
which are held in the mouth or under the
tongue.

Advantages
− Rapid absorption
− Drug stability
− Avoid first-pass effect

Disadvantages

inconvenient

small doses

unpleasant taste of
some drugs

18. Oral

Advantages

Convenient - can be self- administered, pain free,
easy to take

Absorption - takes place along the whole length of
the GI tract

Cheap - compared to most other parenteral routes

19. 
Disadvantages

Sometimes inefficient - only part of the drug may
be absorbed

First-pass effect - drugs absorbed orally are
initially transported to the liver via the portal vein

Irritation to gastric mucosa - nausea and vomiting

Destruction of drugs by gastric acid and digestive
juices

Effect too slow for emergencies

Unpleasant taste of some drugs

Unable to use in unconscious patient
Oral

20. Parenteral Routes

Intravenous (IV)- placing a drug directly into the blood
stream

Intramuscular (IM) - drug injected into skeletal muscle

Subcutaneous - Absorption of drugs from the
subcutaneous tissues

Inhalation - Absorption through the lungs

21. Intravenously
(IN-truh-VEE-nus) Adv: intravenously. Within a blood
vessel . When fluids and drugs are administered
slowly into a blood vessel
Absorption phase is bypassed
(100% bioavailability)
1.precise, accurate and almost immediate onset of
action,
2. large quantities can be given, fairly pain free
3. greater risk of adverse effects
a. high concentration attained rapidly

23. Intramuscular
1. very rapid absorption of drugs in aqueous solution
2.repository and slow release preparations
3.pain at injection sites for certain drugs
(in-trah-MUS-kyoo-lar) Within or into muscle

24. KML
Subcutaneous
1.slow and constant absorption
2.absorption is limited by blood flow
sub-kew-TAY-nee-us:. Beneath the skin.

25. Inhalation
1.rapid onset of action due to rapid access to circulation
a.large surface area
b.thin membranes separates alveoli from circulation
c.high blood flow

26. Topical
•Mucosal membranes (eye drops, antiseptic, sunscreen, callous
removal, nasal, etc.)
•Skin
a. Dermal - rubbing in of oil or ointment (local action)
b. Transdermal - absorption of drug through skin (systemic
action)
i. stable blood levels
ii. no first pass metabolism
iii. drug must be potent or patch becomes to large

28. THANK YOU
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