APA Dictionary of Psychology

n. a morphine-derived opioid antagonist that prevents the binding of opioids to opioid receptors, having primary activity at the mu opioid receptor. Like other opioid antagonists, it can quickly reverse the effects of opioid overdose and is useful in emergency settings to reverse respiratory depression. It has poor oral and sublingual bioavailability and must be dosed parenterally. U.S. trade name: Narcan. In combination with buprenorphine, it is used as an alternative to methadone maintenance therapy (U.S. trade name: Suboxone).