[2] It was reproduced in 1963 by a research group at MacFarlan Smith in Gorgie, Edinburgh, led by Kenneth Bentley.

Diprenorphine (Revivon) is an opioid receptor antagonist that can be administered in proportion to the amount of etorphine used (1.3 times) to reverse its effects.

The LD50 in humans is 3 μg which led to the requirement that the medicine include an equivalent dose of an antidote.

The high incidence of side effects, including severe cardiopulmonary depression, has caused etorphine to fall into disfavor in general veterinary practice.

[5] Etorphine is a potent, non-selective full agonist of the μ-, δ-, and κ-opioid receptors.

Possession of the substance for consumption without license from the Department of Health is illegal with a $1,000,000 (HKD) fine and/or 7 years of jail time.