Etorphine is an extremely potent full agonist notable for its rapid effect. This drug is between 10,000 and 30,000 times more potent an analgesic than morphine, and is currently illegal for non-veterinary use in many countries. Although it has unfavorable side effects, such as extreme cardiopulmonary depression, it is useful in sedating very large animals which need to be subdued quickly. In humans, a lethal dose of etorphine is three micrograms.
