Metazocine is a synthetic opioid analgesic with reinforcing properties and PCP-like activity. Metazocine is a Schedule II controlled substance. Metazocine acts as a ligand at opioid, sigma and NMDA receptors. Metazocine enantiomers exert different pharmacological activity.

Metazocine:
https://drugs.ncats.io/drug/XD53YGT34W

While metazocine has significant analgesic effects, mediated through a mixed agonist - antagonist action at the mu opioid receptor, its clinical use is limited by dysphoric and hallucinogenic effects which are most likely caused by activity at kappa opioid receptors (where it is a high-efficacy agonist) and/or sigma receptors.