Oxilorphan is an opioid

Opioid

An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...

 antagonist from the morphinan

Morphinan

Morphinan is the base chemical structure of a large chemical class of psychoactive drugs, consisting of opioid analgesics, cough suppressants, and dissociative hallucinogens, among others.- Chemical Derivatives :Immediate derivatives of morphinan include:...

 family of drugs.

Oxilorphan is a non-selective opioid which is a μ

Mu Opioid receptor

The μ-opioid receptors are a class of opioid receptors with high affinity for enkephalins and beta-endorphin but low affinity for dynorphins. They are also referred to as μ opioid peptide receptors. The prototypical μ receptor agonist is the opium alkaloid morphine; μ refers to morphine...

 antagonist but a κ

Kappa Opioid receptor

The κ-opioid receptor is a protein that in humans is encoded by the OPRK1 gene. The κ-opioid receptor is one of five related receptors that bind opium-like compounds in the brain and are responsible for mediating the effects of these compounds...

 partial agonist. It has similar effects to naloxone

Naloxone

Naloxone is an opioid antagonist drug developed by Sankyo in the 1960s. Naloxone is a drug used to counter the effects of opiate overdose, for example heroin or morphine overdose. Naloxone is specifically used to counteract life-threatening depression of the central nervous system and respiratory...

, and around the same potency as an antagonist.

Oxilorphan has some weak partial agonist effects and can produce hallucinogenic effects at high doses, suggesting some kappa opioid agonist action. It was trialled for the treatment of opiate addiction, but was not developed commercially.