Curare

Curare refers to a family of plant-derived alkaloids historically used as arrow poisons by Indigenous peoples of South America. The extracts were typically obtained from species such as Chondrodendron tomentosum and Strychnos spp. The term has since been applied to the class of non-depolarizing neuromuscular blocking agents in medicine, most famously d-tubocurarine.

Pharmacology: Curare alkaloids are competitive antagonists of nicotinic acetylcholine receptors at the motor end plate. By occupying the receptor, they prevent acetylcholine-induced depolarization, producing flaccid paralysis. They do not cross the blood-brain barrier in significant amounts and thus do not cause anesthesia or pain relief themselves. They are typically given intravenously in surgical settings.

Medical use: In anesthesia, curare-type agents provide muscle relaxation to facilitate endotracheal intubation and surgical procedures. The original d-tubocurarine has largely been replaced by newer agents such as atracurium, vecuronium, rocuronium, and cisatracurium, which offer more predictable onset, duration, and fewer histamine-related side effects. Reversal of blockade is accomplished with acetylcholinesterase inhibitors to increase acetylcholine at the neuromuscular junction, sometimes with adjuncts like sugammadex for certain agents.

Safety: Paralysis requires ventilation support. Side effects vary by agent and can include hypotension from histamine release or bradycardia. Careful dosing and monitoring are essential, particularly in patients with organ dysfunction or interacting medications.