A 21-year-old lady with a history of hypersensitivity to neostigmine is posted for an elective caesarean section under general anesthesia. Which is the BEST muscle relaxant of choice in this patient ?

Atracurium is a sho acting nondepolarizing muscle relaxant. Neostigmine is given for reversal of the action of non-depolarizing muscle relaxants. Since this patient has a history of hypersensitivity to neostigmine, atracurium can be used in this patient as it does not require reversal. Nondepolarizing muscle relaxants acts by blocking the postsynaptic receptors in a competitive manner so that acetylcholine cannot occupy the receptors to activate depolarization. Neostigmine acts by inhibiting the enzyme acetylcholinesterase in the cleft of neuromuscular junctions which inturn leads to building up of acetylcholine in the synaptic cleft thereby reversing the effects of non depolarizing muscle relaxants that are competitive agonists. Ref: Textbook Of Pharmacology By Seth page 54. The Hands-on Guide to Clinical Pharmacology By Sukhdev Chatu page 210.