Alcuronium chloride (formerly marketed as Alloferin) is a neuromuscular blocking (NMB) agent, alternatively referred to as a skeletal muscle relaxant. It is a semi-synthetic substance prepared from C-toxiferine I,[1] a bis-quaternary alkaloid obtained from Strychnos toxifera. C-toxiferine I itself has been tested for its pharmacological action and noted to be a very long acting neuromuscular blocking agent[2] For a formal definition of the durations of actions associated with NMB agents, see page for gantacurium. The replacement of both the N-methyl groups with N-allyl moieties yielded N,N-diallyl-bis-nortoxiferine, now recognized as alcuronium.
Inclusion of the allylic functions presented an enhanced potential area of biotransformation, and thus alcuronium is observed to have a much shorter duration of neuromuscular blocking action than its parent C-toxiferine I.[3] It also has a more rapid onset of action, and is ~1.5 times as potent as tubocurarine.[4] The pharmacological action of alcuronium is readily reversed by neostigmine, and it produces little histamine release.[5] The major disadvantage of alcuronium is that it elicits a vagolytic effect produced by a selective atropine-like blockade of cardiac muscarinic receptors.[4][6][7]
Zahn K, Eckstein N, Tränkle C, Sadée W, Mohr K (2002). "Allosteric modulation of muscarinic receptor signaling: alcuronium-induced conversion of pilocarpine from an agonist into an antagonist". J Pharmacol Exp Ther. 301 (2): 720–8. doi:10.1124/jpet.301.2.720. PMID11961078. S2CID534003.
Maass A, Mohr K (1996). "Opposite effects of alcuronium on agonist and on antagonist binding to muscarinic receptors". Eur J Pharmacol. 305 (1–3): 231–4. doi:10.1016/0014-2999(96)00240-3. PMID8813558.
Jakubík J, Tucek S (1994). "Protection by alcuronium of muscarinic receptors against chemical inactivation and location of the allosteric binding site for alcuronium". J Neurochem. 63 (5): 1932–40. doi:10.1046/j.1471-4159.1994.63051932.x. PMID7931349. S2CID23053191.
Proska J, Tucek S (1994). "Mechanisms of steric and cooperative actions of alcuronium on cardiac muscarinic acetylcholine receptors". Mol Pharmacol. 45 (4): 709–17. PMID8183250.