On the pharmacology of Org 6338 (2beta, 16beta-dipiperidino - 5alpha - androstan - 3alpha - ol acetate dimethobromide), a new steroidal neuromuscular blocking agent.

Org 6368 is a homologue of pancuronium bromide. Its interactions with other agents in the cat sciatic nerve-gastrocnemius muscle preparation revealed that paralysis was of the non-depolarizing type. This was confirmed in experiments using avian muscle. Org 6368 is a potent muscle relaxant being 2-4 times as potent as (+)-tubocurarine in the cat. Paralysis in the cat is rapid in onset and of appreciably shorter duration than that of pancuronium and (+)-tubocurarine. Repeated injections of the same dose of Org 6368 show no cumulative effect. Muscle relaxant doses generally cause a slight increase in both blood pressure and heart rate. Although its histamine-releasing capacity is greater than that of pancuronium it is less than that of (+)-tubocurarine. Org 6368 shares with pancuronium a very weak effect on both the muscarinic receptor and ganglionic transmission. Differences in the muscle relaxant profiles of Org 6368 and pancuronium are discussed.