Pharmacodynamics Quiz

Study Notes

Pharmacological Actions and Effects of Drugs

Drugs can have 7 main actions: stimulating, depressing, blocking, stabilizing, exchanging, direct beneficial chemical reaction, and direct harmful chemical reaction.
The desired activity of a drug is mainly due to successful targeting of cellular membrane disruption, chemical reactions with downstream effects, interaction with enzyme proteins, structural proteins, carrier proteins, ion channels, and ligand binding to receptors.
General anesthetics were once thought to work by disordering neural membranes and altering Na+ influx, while antacids and chelating agents combine chemically in the body.
Enzyme-substrate binding alters the production or metabolism of key endogenous chemicals, for example, aspirin irreversibly inhibits the enzyme prostaglandin synthetase.
The widest class of drugs act as ligands that bind to receptors, eliciting their normal action (agonist), blocked action (antagonist), or even action opposite to normal (inverse agonist).
The therapeutic window is the amount of medication between the effective dose and the amount that gives more adverse effects than desired effects.
The duration of action of a drug is a function of several parameters including plasma half-life, the time to equilibrate between plasma and target compartments, and the off rate of the drug from its biological target.
In recreational psychoactive drug spaces, duration refers to the length of time over which the subjective effects of a psychoactive substance manifest themselves.
The total duration of a substance is the amount of time it takes for the effects of a substance to completely wear off into sobriety, starting from the moment the substance is first administered.
The onset phase is the period until the very first changes in perception (i.e. "first alerts") are able to be detected.
The "come up" phase is the period between the first noticeable changes in perception and the point of highest subjective intensity, colloquially known as "coming up."
The peak phase is the period of time in which the intensity of the substance's effects is at its height.