What medication is commonly used to treat opioid cravings?

Naltrexone is commonly used to treat opioid cravings due to its mechanism as an opioid receptor antagonist. By blocking the effects of opioids, naltrexone reduces the reinforcing effects that opioids have on the brain, which can help individuals maintain abstinence from opioid use. It is particularly effective in preventing relapse in individuals who have completed detoxification from opioids, as it diminishes the euphoric effects that might occur if opioids are ingested while naltrexone is in the system.

In contrast, disulfiram is primarily used for treating alcohol dependence by causing unpleasant effects when alcohol is consumed, but it does not address opioid cravings specifically. Varenicline is used for smoking cessation by targeting nicotine receptors, thus it is not applicable to opioid cravings. Flumazenil is a benzodiazepine antagonist and is used in cases of benzodiazepine overdose, making it unrelated to the treatment of opioid dependence or cravings.