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How does naltrexone make you feel?

Medically reviewed by Sally Chao, MD. Last updated on May 2, 2025.

Official answer

by Drugs.com

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. It may change the way you feel in other ways, if you have side effects, but not everyone has them.

The most common possible side effects include:

  • Insomnia
  • Anxiety
  • Restlessness
  • Nausea
  • Vomiting
  • Headache
  • Dizziness
  • Joint and muscle pain
  • Decreased appetite

In some cases, naltrexone may cause liver damage. This may cause severe stomach pain and tiredness, and you may notice dark urine or yellowing eyes.

Naltrexone should not be used while you are taking opioids. It takes about 7 to 10 days for opioids to clear from your body. If you take naltrexone before opioids are out of your system, it may change the way you feel because you may have withdrawal symptoms. These may include:

  • Sweating
  • Chills
  • Shaking
  • Nausea
  • Vomiting

If you take naltrexone while you still have alcohol in your system, you may feel nauseous.

How naltrexone works

Naltrexone is used for the treatment of opioid use disorder or alcohol use disorder. This type of treatment is called medication-assisted treatment (MAT).

Opioids act on brain receptors called opioid receptors. When these receptors are activated, they cause the pleasurable symptom called euphoria. Naltrexone blocks these receptors and stops your brain from feeling the “high” or craving an opioid. Opioids include hydrocodone, oxycodone, morphine and heroin.

When used for alcohol use disorder, naltrexone blocks endorphin receptors and keeps alcohol from causing euphoria. Blocking these receptors reduces alcohol cravings.

Using naltrexone along with counseling and behavioral therapy can help people with opioid and alcohol use disorder recover.

Naltrexone comes as a tablet with the brand name ReVia. It also comes as an injection with the brand name Vivitrol. When taken as an injection, there may be reactions at the injection site that include pain, swelling, itching and tenderness.

Other drugs used for opioid use disorder, like methadone, are themselves opioids. Although they are safe when used as prescribed, they can be abused and can become addictive. Naltrexone is not an opioid. There is no abuse potential, and it is not addictive.

Related questions

References
  1. Substance Abuse and Mental Health Services Administration (SAMHSA). Naltrexone. September 15, 2020. Available at: https://www.samhsa.gov/medication-assisted-treatment/medications-counseling-related-conditions/naltrexone. [Accessed April 13, 2021].
  2. National Alliance on Mental Illness (NAMI). Naltrexone (ReVia). January 2021. Available at: https://nami.org/About-Mental-Illness/Treatments/Mental-Health-Medications/Types-of-Medication/Naltrexone-(ReVia). [Accessed April 13, 2021].
  3. U.S. National Library of Medicine (MedlinePlus). Methadone. February 15, 2021. https://medlineplus.gov/druginfo/meds/a682134.html. [Accessed April 13, 2021].
  4. U.S. Food and Drug Administration (FDA). Revia. October 2013. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/018932s017lbl.pdf. [Accessed April 15, 2021].

Read next

Should I take naltrexone in the morning or at night?

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

Does naltrexone cause weight gain?

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 vs naltrexone: How do they compare?

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

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