Examples

Naltrexone is available in pill form. Vivitrol is taken as a shot (injection) into a muscle (intramuscular) once a month.

How It Works

Naltrexone is an opioid antagonist that interferes with the part of the brain involved in producing the pleasure you get from drinking alcohol or taking other drugs.

Why It Is Used

Naltrexone is used to treat alcohol or opioid drug dependence. It reduces the pleasurable effects of alcohol and helps block the effects of narcotic (opioid) drugs, such as heroin. It may help reduce your cravings for opioid drugs.

Naltrexone can be used alone or combined with other medicines that affect the brain, such as medicines for depression or acamprosate. Acamprosate often is used to treat alcohol dependence.

How Well It Works

Most studies show that naltrexone significantly reduces your chance for relapse after you have stopped drinking. ¹ Naltrexone works best to help you stop drinking if you also get counseling. ²

Naltrexone can help prevent drug cravings and relapse, but you still need other treatments, such as counseling, to help you recover from drug addiction.

Side Effects

Naltrexone can cause nausea, dizziness, and fatigue. It also can cause headaches and make you feel anxious, sleepy, or nervous.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

You might develop liver damage if you have liver disease (such as hepatitis, cirrhosis, or liver failure) and take too much naltrexone.

This medicine will cause withdrawal symptoms if you are taking opioids drugs. If you have taken opioids in the past 7 to 10 days, talk to your doctor before taking naltrexone.

You might need to take naltrexone for several months to effectively prevent relapse.

Vivitrol, a once-a-month injection of this medicine, is approved by the U.S. Food and Drug Administration (FDA) to treat drinking problems. This form of naltrexone can be useful for people who have a hard time deciding whether to take the medicine each day.

The U.S. Food and Drug Administration (FDA) has issued an advisory about injectable forms of naltrexone. You may have a skin reaction at the injection site, the place where the shot is given. Call your doctor if you notice any skin change at the injection site, such as swelling, tenderness, redness, or pain, that does not improve or gets worse within 2 weeks.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

Citations

1. Kiefer F, et al. (2003). Comparing and combining naltrexone and acamprosate in relapse prevention of alcoholism: A double-blind, placebo-controlled study. Archives of General Psychiatry, 60(1): 92-99.

2. Srisurapanont M, Jarusuraisin N (2007). Opioid antagonists for alcohol dependence. Cochrane Database of Systematic Reviews (1).

Other Works Consulted

• Beich A, et al. (2002). Screening and brief intervention for excessive alcohol use: Qualitative interview study of the experiences of general practitioners. BMJ, 325(7369): 870.