Cyprenorphine (the hallucinogenic opioid)
Cyprenorphine (M-285) is a drug which is an opioid derivative. It is related to more well-known opioids such as buprenorphine, which is used as an analgesic and for the treatment of opioid addiction, and diprenorphine, which is used as an antidote to reverse the effects of other opioids.

Cyprenorphine has mixed agonist-antagonist effects at opioid receptors, like those of buprenorphine. However the effects of cyprenorphine are somewhat different, as it produces pronounced dysphoric and hallucinogenic effects which limit its potential use as an analgesic.

Cyprenorphine is a mixed agonist-antagonist of opioid receptors. In clinical trials, administration of cyprenorphine induced psychotomimetic effects in pre-operative patients.

Cyprenorphine:
https://drugs.ncats.io/drug/7OP86J5E33

An opioid drug. It is related to more well-known opioids such as buprenorphine, which is used as an analgesic and for the treatment of opioid addiction. However the effects of cyprenorphine are somewhat different, as it produces pronounced dysphoric and hallucinogenic effects which limit its potential use as an analgesic.