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Does Vivitrol Cause Fluctuations in Your Weight?

Vivitrol, a medication used to treat addiction, can cause fluctuations in weight.[1] It may sometimes lead to weight gain, but it has also definitively been linked to weight loss.[2] It is even sometimes prescribed for the purpose of weight loss. 

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In people taking the medication for opioid use disorder (OUD) or alcohol use disorder (AUD), it has the potential to cause nausea, vomiting, and a reduced appetite, all of which can potentially cause weight fluctuations.[3]

Does Vivitrol Impact Your Weight?

Vivitrol, which is a brand name for the drug naltrexone, has been linked to weight loss, so much so that it is sometimes used specifically for that purpose. Even in people who are taking it as part of their addiction treatment, weight loss can occur.[1]

Discussed more below, naltrexone can cause nausea, and it has also been linked to reduced food consumption, directly affecting a person’s appetite even if they don’t experience nausea. The medication can also sometimes cause vomiting, especially in people who have difficulty complying with their treatment and staying abstinent from alcohol. 

Research on Vivitrol & Weight Fluctuations

Notable research on this topic include the following findings:

2020 Review From the Archives of Medical Science

A 2020 review of available data on the safety and efficacy of naltrexone for weight loss in adult patients found that the medication can be used as a promising therapy for obese patients. While not directly related to naltrexone use in patients taking it for alcohol use disorder, this review did point out that naltrexone may reduce food consumption through the blockage of a particular endorphin action and the autoinhibition of certain neurons.[2] 

2000 Study From the Journal of Clinical Psychopharmacology

More relevant to Vivitrol as it’s used in addiction treatment, a 2000 study in the Journal of Clinical Psychopharmacology examined naltrexone-induced nausea in patients taking the medication for treatment of alcohol dependence. The study noted that the medication is well tolerated by most people with AUD but that a subset feel nauseous on it, with 15% of the subjects examined in the study reporting moderate to severe nausea. It seems these higher levels of reported nausea were linked to poorer medication compliance and heavier drinking.[4]

This study also found risk of nausea was “significantly predicted by age, gender, intensity of drinking, duration of abstinence, and the interaction of abstinence duration and intensity of drinking.” Younger patients and female patients were associated with higher risks of nausea. Shorter durations of alcohol abstinence were related to higher levels of nausea, especially for lighter drinkers, but higher durations of alcohol abstinence were linked to less nausea, with lighter drinkers seeing less nausea with prolonged abstinence than heavier drinkers.[4] 

Nausea and vomiting can lead to weight loss. Nausea reduces appetite, and if a person vomits, their body cannot effectively absorb nutrients and calories from food.

2011 Study From the Journal of Opioid Management

A 2011 study examined weight changes that occurred among opioid-dependent patients taking either naltrexone or methadone as part of their treatment. Methadone is an opioid agonist, which this study noted is often associated with weight gain. Naltrexone, the drug in Vivitrol, is an opioid antagonist, which the study notes is associated with weight neutrality or weight loss.[5]

Contrary to the other studies discussed, this study didn’t seem to link the use of naltrexone in addiction treatment to weight loss. It found weight change didn’t significantly vary between patients on methadone and patients on naltrexone. In addition, at the three-month and six-month points in treatment, a small trend of weight increase was noted with use of both medications.[5] 

Why Can Weight Be Impacted When Using Vivitrol?

The mechanism by which Vivitrol can impact weight isn’t fully understood. The current literature suggests it’s a combination of factors. First, the medication can directly affect appetite. This is a factor that has been studied more in people prescribed the medication for weight loss, but there is no reason that it wouldn’t also apply to those taking the medication as part of addiction treatment.

When used to treat addiction, nausea is also relatively common with Vivitrol, which can further affect appetite and a person’s ability to eat even if they’re hungry. The evidence-based hypothesis proposed is that “recency and intensity of alcohol use are related to opiate antagonist-precipitated nausea,” with Vivitrol being an opiate antagonist.[4]

With that said, the 2011 study discussed earlier shows that at least some people who take Vivitrol experience weight gain, although the gain doesn’t seem to be especially high. This is an issue that likely should be studied in more detail, as some questions are still unanswered.

Talk to Your Doctor if You Are Concerned About Weight Fluctuations

If you’ve been prescribed Vivitrol to treat addiction or drug dependence, it’s important to understand that weight loss or gain isn’t the goal of your treatment. Additionally, extreme weight fluctuations aren’t considered healthy. 

If you are concerned that you may be losing or gaining weight too quickly, or if weight change is otherwise impacting your quality of life, talk to your doctor. They may be able to provide better solutions for your needs, such as adjusting doses of the medications you take, choosing different medications, or recommending lifestyle changes that can help counter unhealthy weight change. 

As you participate in a comprehensive addiction treatment program, you’ll work on implementing changes to build a healthier life in recovery. This may include implementing some of these lifestyle changes, such as a balanced diet and regular exercise routine.[6] 

Updated April 11, 2024
  1. What is Vivitrol? UAMS Psychiatric Research Institute. Accessed March 29, 2024.
  2. Kulak-Bejda A, Bejda G, Waszkiewicz N. Safety and efficacy of naltrexone for weight loss in adult patients – a systematic review. Archives of Medical Science. Published 2020.
  3. Singh D, Saadabadi A. Naltrexone. StatPearls. Published 2020.
  4. O’Malley SS, Krishnan-Sarin S, Farren C, O’Connor PG. Naltrexone-induced nausea in patients treated for alcohol dependence: Clinical predictors and evidence for opioid-mediated effects. Journal of Clinical Psychopharmacology. 2000;20(1):69-76.
  5. Mysels, MD, MBA DJ, Vosburg, PhD SK, Benga, MD I, Levin, MD FR, Sullivan, MD, PhD MA. Course of weight change during naltrexone versus methadone maintenance for opioid-dependent patients. Journal of Opioid Management. 2011;7(1):47-53.
  6. Patterson MS, Spadine MN, Graves Boswell T, et al. Exercise in the treatment of addiction: A systematic literature review. Health Education & Behavior. Published April 29, 2022:109019812210901.
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