Naltrexone, ReVia®

Brand name

  • ReVia®

Drug Class

Opioid antagonist

  • Naltrexone belongs to a class of drugs known as opiate antagonists.
  • It works in the brain to prevent opiate effects (e.g., feelings of well-being, pain relief). It also decreases the desire to take opiates.
  • This medication is also used to treat alcohol abuse. It can help people drink less alcohol or stop drinking altogether. It also decreases the desire to drink alcohol when used with a treatment program that includes counseling, support, and lifestyle changes.


  • Tablets 50 mg


  • Naltrexone is used to help people who have stopped drinking alcohol or using opioids to prevent relapse.
  • Naltrexone should not be used to treat people who are still using opioids.
  • Naltrexone does not prevent or relieve the withdrawal symptoms, instead, it may cause or worsen withdrawal symptoms.
  • Clinical trials have found naltrexone superior to placebo in reducing risk of relapse and increasing abstention.


  • Naltrexone act as a competitive antagonist at mc, κ, and δ receptors in the CNS, with the highest affintiy for the μ receptor.
  • Naltrexone may block the effects of endogenous opioids which could lead to the antagonization of most of the subjective and objective effects of opiates, including respiratory depression, miosis, euphoria, and drug craving.
  • Naltrexone blocks endogenous opioid receptors, however it is not used for aversive therapy.


Naltrexone is usually stopped at 25 mg once daily and titrated up to 50 mg daily. Some patients would benefit from average dose of 100 mg daily. Maximum daily dose that naltrexone can be taken is 150 mg.

Drug Interactions

Naltrexone interacts with narcotics. You should not take naltrexone if you are still taking any narcotics, methadone or suboxone. Also, naltrexone should not be taken within 7 days of discontinuation of narcotics, methadone or suboxone.

Some products that may interact with naltrexone include:

  • cough medication (e.g., dextromethorphan)
  • disulfiram
  • diarrhea medication (e.g., diphenoxylate)
  • thioridazine

Adverse Effects

A small percentage of patients might experience some of the following symptoms:

  • Anxiety
  • Nervousness
  • Fatigue
  • Dizziness
  • Sleepiness or poor sleep
  • Headache
  • Changes in thinking clearly
  • Stomach upset
  • Rash
  • Itching/swelling (especially of the face/tongue/throat)
  • Trouble breathing

Naltrexone could cause liver injury when taken in excessive doses. Stop using this medication and tell your doctor right away if you develop symptoms of liver disease, including:

  • persistent nausea/vomiting
  • severe abdominal pain
  • dark urine
  • yellowing eyes
  • yellow skin


  • Patients receiving opioid painkillers
  • Individuals who are actively abusing opioids
  • individuals with positive urine test for opioids


  • If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule.
  • Do not double the dose to catch up.


This document is prepared by the “Mental Health for All” team. This document is provided for information purposes only and does not necessarily represent endorsement by or an official position of the Essentials of Medicine. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient’s medical history.

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