Animal pharmacology of Wy-16,225, a new analgesic agent.

The analgesic potency of Wy-16,225 in rodents and primates is greater than morphine while antagonist potency is slightly less than that of nalorphine. The compound demonstrates properties unlike those of standard narcotic and narcotic antagonist agents and has a wide margin of safety. In dependence liability studies, Wy-16,225 neither acutely substitutes for morphine nor produces direct dependence when administered chronically to monkeys. Wy-16,225 has no anti-inflammatory properties, is not constipating in rats, has no significant cardiovascular toxicity in dogs and produces minimal respiratory depression in monkeys.