Naltrexone (INN, BAN, USAN) is an opioid antagonist used primarily in the management of alcohol dependence and opioid dependence. It is marketed in generic form as its hydrochloride salt, naltrexone hydrochloride, and marketed under the trade names Revia and Depade. In some countries including the United States, a once-monthly extended-release injectable formulation is marketed under the trade name Vivitrol. Also in the United States, Methylnaltrexone Bromide, a closely related drug, is marketed as Relistor, for the treatment of opioid induced constipation. Naltrexone should not be confused with naloxone nor nalorphine, which are used in emergency cases of opioid overdose.

The medication works by blocking the effects of opioids, specifically the euphoria or high feeling that leads to increased usage. In the case of alcohol dependence, while the exact way naltrexone works is not completely understood, it’s believed to affect the mechanisms in the brain associated with the rewarding effects of drinking and the craving for alcohol.

Naltrexone is usually taken orally, either daily or three times a week, and it can also be administered as a monthly injectable. It is often prescribed as part of a complete treatment program that includes counseling and group meetings.

It’s important to note that naltrexone won’t cause you to “get sober” if you are currently under the influence of alcohol or drugs, and it doesn’t reduce the effects of alcohol or drugs you take after you’ve taken your dose. It’s intended to help you avoid using these substances in the future.

As with any medication, naltrexone can have side effects, which can include nausea, headache, dizziness, fatigue, and insomnia. It’s also worth noting that a person should not use opioids while taking naltrexone, as it can cause severe withdrawal symptoms. As such, a person should be free from opioids for a certain period before starting naltrexone, as advised by a healthcare professional.

As always, it’s important to discuss the potential benefits, risks, and alternatives with a healthcare provider when considering any medication.