Naltrexone competitively binds to such receptors and may block the effects of endogenous opioids. This leads to the antagonization of most of the subjective and objective effects of opiates, including respiratory depression, miosis, euphoria, and drug craving. Naltrexone is a prescription medication used to treat alcohol use disorder (AUD) and opioid use disorder (OUD) to reduce cravings and help control physiological dependence. Naltrexone works by blocking the effects of alcohol and opioid medications, preventing the euphoria and intoxication (the “buzz”) these substances cause, and it also helps reduce the urge or cravings to use alcohol or opioids.