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Generic name: naltrexone (oral) [ nal-TREX-own ]
Drug classes: Antidotes, Drugs used in alcohol dependence

Medically reviewed by on Feb 9, 2024. Written by Cerner Multum.

What is ReVia?

ReVia is used in adults to treat alcohol dependence and block the effects of opioids.

ReVia may also be used for purposes not listed in this medication guide.

ReVia side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Using opioid medicine while you are taking ReVia could stimulate opioid withdrawal symptoms. Common withdrawal symptoms are craving for opioids, sweating, fever, stomach pain, vomiting, diarrhea, watery eyes, runny or stuffy nose, tingling, goose bumps, body aches, shaking, muscle twitching, trouble sleeping, and feeling anxious, depressed, fearful, restless or uneasy.

ReVia may cause serious side effects. Call your doctor at once if you have:

High doses of naltrexone oral may harm your liver. Stop taking ReVia and call your doctor at once if you have right-sided upper stomach pain, vomiting, loss of appetite, dark urine, clay-colored stools, or yellowing of your skin or eyes.

Common side effects of ReVia may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


You should not be treated with ReVia if you are currently using an opioid analgesic, are addicted to opioids or having opioid withdrawal symptoms, or if you have used any opioid medicine such as, methadone, buprenorphine, tramadol, and others opioids within 7 to 14 days.

You should not use ReVia if you have failed the naloxone challenge test or have tested positive for the urine screen for opioids.

Before taking this medicine

You should not use ReVia if you are allergic to it, or if:

Tell your doctor if you use thioridazine or disulfiram.

Also tell your doctor if you have or have ever had:

It is not known if ReVia will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Ask a doctor if it is safe to breastfeed while using ReVia.

How should I take ReVia?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Your doctor may recommend you have a family member or other caregiver make sure you take ReVia on schedule, to make sure you are using the medicine correctly as part of your treatment.

Wear a medical alert tag or carry an ID card to let others know you use ReVia.

ReVia is only part of a complete treatment program that may also include additional forms of counseling and/or monitoring. Follow your doctor's instructions very carefully.

Store tightly closed at room temperature, away from moisture and heat. Protect from light.

After taking ReVia, your body will be more sensitive to opioids. If you use an opioid medicine in the future, you will need to use less than before the this medicine treatment. Using the same amount you used before could lead to overdose or death.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking ReVia?

Do not use opioid medication, heroin, or other street drugs while you are taking ReVia. Never try to overcome the effects of naltrexone by taking larger amounts of opioids. Doing so could result in dangerous effects, including coma or death.

Ask your doctor before using any medicine to treat a cold, cough, diarrhea, or pain. These medicines may contain opioids and may not work as well while you are taking ReVia.

ReVia may cause dizziness or drowsiness and may impair your reactions. Avoid driving or hazardous activity until you know how this medicine will affect you.

What other drugs will affect ReVia?

Other drugs may affect ReVia, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Popular FAQ

Low dose naltrexone means taking a dose of naltrexone that is up to one-tenth, or 10%, of the dose that is usually taken for opioid addiction. A low dose of naltrexone is approximately 4.5mg of naltrexone a day compared with the usual dosage of naltrexone for opioid addiction which is 50mg to 100mg a day. Continue reading

Naltrexone blocks the feelings of intoxication (the “buzz”) from alcohol when you drink it. This allows people with alcohol use disorder to lessen their drinking behaviors enough to stay in treatment, avoid relapses, and take their medication. Over time, cravings for alcohol will decrease. However, naltrexone will not prevent you from becoming impaired while drinking alcohol. Do not use naltrexone so that you can drive or perform other activities under the influence of alcohol. Continue reading

Do NOT take opiates, including heroin or other prescription or illegal opiates while using naltrexone. Taking opiates with naltrexone increases your risk for an overdose, coma and death. Do not use naltrexone if you are dependent on opioids or if you are experiencing opioid withdrawal symptoms. Naltrexone should not be used before you complete a medically-supervised opioid withdrawal lasting at least 7 to 14 days. Continue reading

The manufacturer does not specify if you should take naltrexone tablets in the morning or at night. Take naltrexone exactly as your doctor orders it. Many patients take their medication in the morning to help affirm their continued treatment success for either opioid use disorder or alcohol use disorder. Taking naltrexone tablets after a meal (for example: breakfast) may help to lessen any stomach side effects such as nausea or pain. Continue reading

Weight gain is not a common side effect with oral naltrexone treatment. When used in combination with bupropion, naltrexone is approved to help promote weight loss. Naltrexone is known to frequently cause stomach side effects like nausea and vomiting, stomach pain or cramping, and loss of appetite which could contribute to weight loss. Weight gain and increased appetite have been reported as a possible side effect, but is not common. Continue reading

Acamprosate and naltrexone are two different medications that are used in the treatment of alcohol use disorder. They work in different ways to help people who are dependent on alcohol to abstain from drinking it. Naltrexone is also used for the treatment of opioid use disorder.

Acamprosate was thought to be slightly more effective at helping people with alcohol use disorder remain off alcohol, while naltrexone was thought to be slightly more effective at helping reduce heavy drinking and cravings, according to the results of a meta-analysis which used data from 64 trials.

Results from two small studies, however, indicate that naltrexone is more effective than acamprosate in a number of areas. Continue reading

When taken as directed, naltrexone may reduce your cravings for alcohol or opioids. You’ll feel less of a need to take drugs or drink. Continue reading

Oral naltrexone is well absorbed and will usually begin working within one hour after a dose. Intramuscular naltrexone is an extended-release formulation and has two peaks, first at 2 hours then again 2 to 3 days later, although its therapeutic effect lasts for one month Continue reading

Naltrexone is a pure opiate receptor antagonist and works by primarily binding at the mu opioid receptors. By binding to these receptors, it blocks the euphoric (pleasurable or "high") effects linked with alcohol use or opioids. Continue reading

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.