Pharmacokinetics Flashcards
Pharmacokinetics
Determination of the time course of disposition of a drug in the body
Factors affecting pharmacokinetics
-Absorption
-Distribution
- Metabolism
- Excretion
What does pharmacokinetics determine within the body?
Determines
1.concentration of drug at its site of action (dose)
2. intensity of effect (response)
What would low absorption mean?
-Would mean insufficient amount of drug reaching the target site and therefore less of an effect
What would altered distribution result in?
Can result in preferential concentration in a non-target organ (eg. adipose tissue) which likely will result in less of an effect and low response to drug
What can metabolism result in?
Can result in the production of a less or more pharmacologically active metabolite or a toxic metabolite
What can slower excretion result in?
Can increase the half-life of a drug and may result in toxicity
What factors influence ADME?
-genetics
-life history (eg. age)
- Environment (eg. diet)
**alters the intensity of effect in an individual animal
Components of absorption
- Drug dose is administered.
- Some of drug falls under liberation into feces (dose never fully absorbed when oral administration) and the rest is absorbed.
3.Drug reaches systemic circulation
Components of distribution
- Free drug and protein (albumen) bound drug are in equilibrium
- Moves to therapeutic site of action, tissue reservoirs, or an unwanted site of action
Components of metabolism
Drug can undergo biotransformation by organs containing hundreds of enzymes.
*Liver is most significant contributor
Components of excretion
Drug is excreted through kidney (urine), liver (bile), lung (expired air)
Pharmacodynamics
-biochemical and physiological effects of drugs and their mechanisms of action
