The science concerned with drugs, their sources, appearance, chemistry, actions and uses.
Any substance other than food which is used in the prevention, diagnosis, alleviation, treatment, or cure of disease.
What a drug does to the body.
What your body does to a drug.
After a drug has entered the body.
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
- Route of administration
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]
The comparison of the amount of a drug that causes the therapeautic effect to the amount that causes toxicity.
The maximal response of a drug. This is seen by the plateau at the top of the curve.
Potency is 50% of the maximal response (efficacy).
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).
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.
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.