physostigmine

Physostigmine is a naturally occurring alkaloid and a reversible cholinesterase inhibitor derived from the Calabar bean. It acts as a parasympathomimetic agent by inhibiting acetylcholinesterase, the enzyme responsible for breaking down acetylcholine. This inhibition increases acetylcholine concentrations at synapses, thereby stimulating both muscarinic and nicotinic receptors throughout the body. Unlike some other anticholinesterases (e.g., neostigmine), physostigmine is a tertiary amine and can cross the blood-brain barrier, making it effective for reversing both central and peripheral effects of anticholinergic toxicity. Clinically, it is used as an antidote to treat anticholinergic poisoning (such as overdoses of atropine, scopolamine, belladonna alkaloids, antihistamines, certain antidepressants), in addition to its historical use in glaucoma therapy. Its poor tolerability has limited its use in chronic conditions like Alzheimer's disease[1][2][5][8].

Brand names

AntiliriumAnticholium

Other names

physostigmine salicylateeserine