An opioid antagonist is a receptor blocker that acts on opioid receptors. Naloxone and naltrexone are commonly used opioid antagonists which competitively bind to opioid receptors with higher affinity than agonists (e.g morphine and natural endorphins) but do not activate the receptors, effectively blocking the receptor. Naloxone reverses the effects of narcotic medication, including extreme drowsiness, slowed breathing, or loss of consciousness. In it's injection form, it is used to diagnose and treat a narcotic overdose in an emergency situation. Naltrexone is used primarily in the management of alcohol dependence and opioid dependence
The mu-opioid receptor (OPRM1) is the primary binding site of action for many opioid drugs and for binding of beta-endorphins. One of the effects of opiate and alcohol use is to increase release of beta-endorphins, which subsequently increases release of dopamine and stimulates cravings. Naloxone binds to OPRM1, preventing beta-endorphin binding and subsequently reducing the craving for substances of abuse.
Related to:
Naloxone, Naltrexone, Narcan, Evzio, Revia, Depade, Vivitrol, Morphine, Buprenorphine