The study of substances that interact with living systems through chemical processes, especially by binding to regulatory molecules and activating or inhibiting normal body processes.
The actions of the drug on the body
The actions of the body on the drug that govern the absorption, distribution, and elimination of drugs.
Define a "drug".
Any substance that brings about a change in biologic function through its chemical actions.
The component of a cell or organism that interacts with a drug and initiates the chain of events leading to the drug's observed effects.
1) determines the quantitive relations between dose or concentration of drug and pharmacologic effects
2) responsible for selectivity of drug action.
3) mediate the actions of pharmacologic agonists and antagonists.
An activator of a receptor when the receptor is occupied. Can be divided into 2 classes: partial agonists and full agonists.
An inhibitor that binds to the receptor but does not activate it. It prevents agonists from activating receptors. It has affinity but not efficacy.
Define partial agonist.
An agonist that produces a lower response (has only partial efficacy) at full receptor occupancy than full agonist by competitively inhibiting the response produced by full agonists.
Define Competitive antagonist.
Receptor antagonist that binds to the receptor but does not stimulate the receptor. It competes with the agonist for receptor-binding sites on the same receptor. Can displace agonists from receptors in sufficient quantities causing a right shift in the dose-response curve.
Define noncompetitive agonist.
An antagonist that binds to a site on the receptor protein separate from the agonist binding site preventing receptor activation without blocking agonist binding.