Nicotinic antagonist

A nicotinic antagonist is a type of anticholinergic drug that inhibits the action of acetylcholine (ACh) at nicotinic acetylcholine receptors. These compounds are mainly used for peripheral muscle paralysis in surgery, the classical agent of this type being tubocurarine,^[1] but some centrally acting compounds such as bupropion, mecamylamine, and 18-methoxycoronaridine block nicotinic acetylcholine receptors in the brain and have been proposed for treating nicotine addiction.

Comparison
Mechanism	Antagonist	Preferred receptor	Clinical use
Ganglionic blocking agents	Hexamethonium	Ganglion type	None^[2]
	Mecamylamine	Ganglion type
	Trimethaphan	Ganglion type	Rarely used for blood pressure decrease during surgery^[2]
Nondepolarizing neuromuscular blocking agents	Atracurium	Muscle type	Muscle relaxant in anaesthesia^[2]
	Doxacurium	Muscle type
	Mivacurium	Muscle type
	Pancuronium	Muscle type	Muscle relaxant in anaesthesia^[2]
	Tubocurarine	Muscle type	Discovered in arrow poison it was the first pheripheral muscle relaxant. Rarely used since 1980s.^[2]
	Vecuronium	Muscle type	Muscle relaxant in anaesthesia^[2]
Depolarizing neuromuscular blocking agents	Succinylcholine*	Muscle type
Centrally acting nicotinic antagonists	18-Methoxycoronaridine	α3β4
	Bupropion	α3β4. α4β2, α1β1γδ	Antidepressant (NDRI)
	Hydroxybupropion	α3β4. α4β2, α1β1γδ	Antidepressant (NDRI). Metabolite of bupropion.
	Threohydrobupropion	α3β4.	Antidepressant (NDRI). Metabolite of bupropion.
	Dextromethorphan	α3β4. α4β2, α7	Common over the counter antitussive.
	Dextrorphan	α3β4. α4β2, α7	Metabolite of dextromethorphan; no accepted medical uses.
	3-Methoxymorphinan	α3β4	Secondary metabolite of dextromethorphan; not used in medical practice. Unknown medical efficacy.

Note: Succinylcholine is a nicotinic agonist. See neuromuscular blocking agents page for details on the mechanism of action.

References

↑ P. Taylor (1990). In Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th Ed., (A. G. Gilman et al., Eds.), pp. 166-186, New York: Pergamon Press.
1 2 3 4 5 6 Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. ISBN 0-443-07145-4. Page 149

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