Parasympathomimetic drug

A parasympathomimetic drug, sometimes called a cholinomimetic drug, is a substance that stimulates the parasympathetic nervous system (PSNS). These chemicals are also called cholinergic drugs because acetylcholine (ACh) is the neurotransmitter used by the PSNS. Chemicals in this family can act either directly by stimulating the nicotinic or muscarinic receptors (thus mimicking acetylcholine), or indirectly by inhibiting cholinesterase, promoting acetylcholine release, or other mechanisms.

Some chemical weapons such as sarin or VX, non-lethal riot control agents such as tear gas, and insecticides such as diazinon fall into this category.

For a cholinergic agent, the following criteria describe the structure activity relationship:

These act by stimulating the nicotinic or muscarinic receptors.

Indirect acting parasympathomimetic drugs may be either reversible cholinesterase inhibitors, irreversible cholinesterase inhibitors or drugs that promote ACh release or anti-adrenergics. The latter inhibits the antagonistic system, the sympathetic nervous system.

See also: alpha blocker and beta blocker

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