MUSCLE RELAXANTS

Neuromuscular blocking drugs or muscle relaxants are firmly entrenched as an integral part of everyday anesthetic practice (see Chapter 13 ). Anesthesia providers practiced for nearly 100 years without these drugs, but it would be difficult to provide the same level of anesthetic service today without their use.

Initial Contact with Arrow Poison

Homer (Odyssey, I, 260) and Virgil (Aeneid, IX, 772) mention poisoned arrows. The word toxin is derived from the Greek root toxon ("bow"). Medical fascination with the specific arrow poison now called curare began nearly 500 years ago when the first returning explorers from South America told of a poisoned arrow that was used in warfare and to kill game.^[322] In 1505, Pietro Martyr d'Anglera,^[323] an Italian monk who visited South America in the early 16th century, wrote the following:

This Indian King layd wait for oure men ... set on them with about seven hundred men armed after theire maner, although they were naked. For only the King and his noblemen were appareled. ... So fiercely assayling oure men with theire venomous arrowes that they slewe of them fortie and seven ... for that poyson is of such force, that albeit the wounds were not great, yet they dyed thereof immediately.

Sir Walter Raleigh^[324] (1552–1618) was one of the first to report on the wonders of the drug, which his first lieutenant, Laurence Keymis, called ourari, the first English attempt to reproduce the Macusi Indian pronunciation of the poison. Remarkably, the flesh of the poisoned animal was eaten with impunity. The native inhabitants were greatly impressed with gunpowder but noticed that the noise from guns frightened the game, and they preferred the poison-tipped arrow that was sent quietly from a blowgun. Initial reports indicated that the poison was made from a mixture of rat bones and bark.

Charles-Marie de la Condamine^[325] (1701–1774) was the first to bring creditable samples back to Europe. His samples were used by Richard Brocklesby (1722–1797) to demonstrate that the heart of a cat continued to beat for 2 hours after it was apparently dead from curare poisoning. The Florentine Abbot, Felix Fontana (1720–1805), injected the drug directly into the exposed sciatic nerve and observed no effect. He concluded that the curare impaired the irritability of the muscle.^[326]