curar

Curare refers to a family of plant-derived alkaloid compounds used as arrow poisons by Indigenous peoples of South America. The term historically describes extracts from several plants, most famously the vine Chondrodendron tomentosum, with other species such as Strychnos toxifera also used to produce curare-type toxins. These preparations were traditionally applied to arrow tips to immobilize game by causing rapid, powerful paralysis.

Pharmacology and mechanism of action: Curare works as a competitive antagonist of nicotinic acetylcholine receptors at the neuromuscular junction. By blocking acetylcholine from activating these receptors, curare prevents muscle contraction, resulting in flaccid paralysis. The effect is limited to peripheral nerves and does not affect consciousness or perception, as it does not cross the blood-brain barrier. Curare is not effective when taken by mouth and is typically administered by injection in controlled settings.

Medical use and evolution: In modern medicine, curare-like alkaloids and their synthetic derivatives are used as non-depolarizing neuromuscular blocking agents to facilitate anesthesia, endotracheal intubation, and mechanical ventilation. Examples include d-tubocurarine and newer agents such as atracurium and rocuronium. Dosing is carefully titrated, and reversal agents such as acetylcholinesterase inhibitors may be used at the end of a procedure to restore muscle function.

Safety and history: Curare’s historical use as a hunting poison contrasts with its contemporary medical applications, which require strict clinical supervision. Side effects can include hypotension and histamine release, particularly with older compounds; modern agents have improved safety profiles. The term curare encompasses a class of related compounds rather than a single chemical substance.