Acetorphine is a synthetic narcotic pain reliever.

Acetorphine is a synthetic narcotic analgesic. Acetorphine was reported to have uses in veterinary medicine with pronounced advantages in the immobilization of the giraffe in which toxic effects were reduced as compared to the effects of etorphine. In July 1966, the Director-General of the World Health Organization informed the Secretary-General that WHO had arrived at the conclusion that etorphine and acetorphine should be included in Schedule I of the Convention, since they could give rise to similar abuse, and produce similar ill effects as the substances already listed therein. Acetorphine is a Schedule I controlled substance in the United States.

Acetorphine:
https://drugs.ncats.io/drug/2OGQ81529L

Acetorphine is a potent opioid analgesic, up to 8700 times stronger than morphine by weight. It is a derivative of the more well-known opioid etorphine, which is used as a very potent veterinary painkiller and anesthetic medication, primarily for the sedation of large animals such as elephants, giraffes and rhinos.