Tubocurarine chloride

Tubocurarine (also known as d-tubocurarine or DTC) is a toxic benzylisoquinoline alkaloid historically known for its use as an arrow poison. In the mid-1900s, it was used in conjunction with an anesthetic to provide skeletal muscle relaxation during surgery or mechanical ventilation. Safer alternatives, such as cisatracurium and rocuronium, have largely replaced it as an adjunct for clinical anesthesia and it is now rarely used. The specific form used was tubocurarine chloride, its hydrated hydrochloride salt.

History

Tubocurarine is a naturally occurring mono-quaternary alkaloid obtained from the bark of the Menispermaceous South American plant Chondrodendron tomentosum, a climbing vine known to the European world since the Spanish conquest of South America. Curare had been used as a source of arrow poison by South American natives to hunt animals, and they were able to eat the animals' contaminated flesh subsequently without any adverse effects because tubocurarine cannot easily cross mucous membranes. Thus, tubocurarine is effective only if given parenterally, as demonstrated by Bernard, who also showed that the site of its action was at the neuromuscular junction. Virchow and Munter confirmed the paralyzing action was limited to voluntary muscles. In 1943, Oskar Wintersteiner and J. D. Dutcher isolated crystalline d-tubocurarine from curare prepared solely from Chondrodendron tomentosum, confirming the plant as a source of the active alkaloid in some curare preparations. They noted that pure crystalline preparations were needed for physiological and clinical studies in medicine because curare preparations available at that time varied in their botanical origin, composition, and potency.