31. Naloxone or naltrexone is the preferred human opioid receptor antagonist. 32. More recently, Canada made the opioid a Schedule I controlled drug. 33. Dezocine is a mixed agonist / antagonist of opioid receptors. 34. Semorphone is a partial agonist at ?-opioid receptors. 35. It is related to etonitazene, an opioid of significantly higher potency. 36. This inhibits the breakdown of the endogenous opioid peptides known as enkephalins. 37. Additionally, opioid drugs suppress nociceptions by binding to endogenous opioid receptors. 38. Additionally, opioid drugs suppress nociceptions by binding to endogenous opioid receptors. 39. Despite its proteolytic degradation relative to many other opioid peptides. 40. It is an agonist for the ?-opioid receptors.
