August 10, 2015 - Pharmacology Basics Flashcards
Pharmacology
The science concerned with drugs, their sources, appearance, chemistry, actions and uses.
Drug Definition
Any substance other than food which is used in the prevention, diagnosis, alleviation, treatment, or cure of disease.
Pharmacodynamics
What a drug does to the body.
Pharmacokinetics
What your body does to a drug.
ADME
After a drug has entered the body.
Absorption
Distribution
Metabolism
Elimination
Absorption of a Drug
Passage of a drug from its site of administration into the systemic circulation.
Factors Affecting Absorption
- Surface area
- Blood flow
- Contact time
- pH
- Food
- Route of administration
Bioavailability
The fraction of a drug that reaches systemic circulation after a particular route of administration.
First Pass Metabolism
The drug gets filtered through the liver before going into systemic circulation. The amount of the drug that makes it through the liver is the bioavailability of the drug.
Apparent Volume of Distribution
Theoretical volume of fluid into which the drug is distributed.
Volume of distribution = total amount of drug in the body / [drug blood plasma]
Therapeutic Index
The comparison of the amount of a drug that causes the therapeautic effect to the amount that causes toxicity.
Efficacy
The maximal response of a drug. This is seen by the plateau at the top of the curve.
Potency
Potency is 50% of the maximal response (efficacy).
Agonist
A drug that binds to a receptor and produces a functional response. It may be a full agonist, a partial agonist (doesn’t reach as high), or an inverse agonist (acts to produce the opposite effect).
Antagonist
A chemical that can decrease or abolish the efefct of an agonist at the level of receptor or produce a response that is opposite to the agonist. It may be competitive in which the agonists and antagonists are competing for the same active site, or may be non-competitive in which it binds allosterically.
Steady State Concentration
When the rate of drug imput equals the rate of drug elimination.
Loading Dose
When a massive dose is administered to rapidly establish the effective concentration of the drug. Maintenance doses are then administered afterwards to maintain the desired steady-state.
