Naltrexone (Vivitrol®) is a once-monthly injectable medication used to treat alcohol and opioid use disorders by blocking the pleasurable effects of these substances.
Naltrexone
*image for illustrative purpose only
Naltrexone
*image for illustrative purpose only
Naltrexone is the active ingredient in the brand-name drug Vivitrol®, an injectable medication used to prevent relapse in people with alcohol and opioid dependence. While Vivitrol is a once-monthly injection, naltrexone is also available as a daily pill. Healthcare providers may, at their own discretion, prescribe it off-label to help support weight loss efforts.
The medication works by blocking the pleasurable effects of opioids and alcohol, which helps reduce cravings and makes relapse less likely. It’s FDA-approved to treat alcohol use disorder and opioid use disorder.
Common side effects include nausea, vomiting, dizziness, decreased appetite, and injection site reactions, while serious risks include liver damage and symptoms of sudden opioid withdrawal. People with liver disease or who have recently used opioids should be cautious about using this drug.
Vivitrol (naltrexone) is indicated:
For the treatment of alcohol dependence in patients who are able to abstain from alcohol in an outpatient setting prior to initiation of treatment with Vivitrol. Patients should not be actively drinking at the time of initial Vivitrol administration
For the prevention of relapse to opioid dependence, following opioid detoxification
Vivitrol should be part of a comprehensive management program that includes psychosocial support
Opioid antagonist
The adverse events seen most frequently in association with Vivitrol therapy for alcohol dependence (i.e, those occurring in ≥5% and at least twice as frequently with Vivitrol than placebo) include:
Nausea
Vomiting
Injection site reactions (including induration, itchiness, nodules, and swelling)
Muscle cramps
Dizziness or fainting
Sleepiness or sedation
Anorexia
Decreased appetite or other appetite disorders
The adverse events seen most frequently in association with Vivitrol therapy in opioid-dependent patients (i.e., those occurring in ≥2% of patients treated with Vivitrol and at least twice as frequently with Vivitrol than placebo) were:
Liver enzyme abnormalities
Injection site pain
Inflammation of the nose and throat
Insomnia
Toothache
The cost of naltrexone varies depending on your insurance plan, which pharmacy you use, the dosage, and the quantity. Without insurance, generic naltrexone may cost about $35 for 20 oral tablets or about $86 for 60 tablets. A once-monthly injection of Vivitrol costs about $1,700 without insurance. Insurance plans may cover all or some of the costs.
You may also be eligible for manufacturer coupons, discount cards, or patient assistance programs if you meet certain criteria. Ask your provider or pharmacist if you qualify.
Hers offers access to personalized Weight Loss Medication Kits, which may feature a compounded version of naltrexone** in addition to other oral medications that may support weight loss.
Hers Weight Loss Medication Kits start at $69 per month. This price includes the many benefits of the Hers app, such as unlimited messaging with your care team, recipes and healthy eating tips, and behavior change exercises.
**Compounded medications are not approved or evaluated for safety, effectiveness, or quality by the FDA.
You can get a prescription for naltrexone after being evaluated by a healthcare provider who can determine if the medicine is right for you based on factors like your symptoms and medical history.
If you’re interested in naltrexone for weight loss, you can connect with a licensed healthcare provider on the Hers platform. They will create a personalized weight loss treatment plan that fits your needs.
When you access weight loss medication through the Hers platform, your medication is shipped directly to your door. You get all the supplies you need, along with instructional videos, ongoing provider support through the app, and a wealth of holistic health resources like meal plans, recipes, and fitness content.
Patients receiving opioid analgesics
Patients with current physiologic opioid dependence
Patients in acute opioid withdrawal
Any individual who has failed the naloxone challenge test or has a positive urine screen for opioids
Patients who have previously exhibited hypersensitivity to naltrexone, polylactide-co-glycolide (PLG), carboxymethylcellulose, or any other components of the diluent
Naltrexone antagonizes the effects of opioid-containing medicines, such as cough and cold remedies, antidiarrheal preparations, and opioid analgesics
Vulnerability to opioid overdose
Injection site reactions
Precipitation of opioid withdrawal
Liver toxicity
Depression and suicidality
When reversal of Vivitrol blockade is required for pain management: In an emergency situation in patients receiving Vivitrol, suggestions for pain management include regional analgesia or use of non-opioid analgesics
Eosinophilic pneumonia
Hypersensitivity reactions including anaphylaxis
Other drugs are available that can help. Some may be better suited for you than others.
Examples of other medications used to help with weight loss include:
Wegovy® (semaglutide)
Contrave® (naltrexone-bupropion)
Qsymia® (phentermine-topiramate)
Saxenda® (liraglutide)
Xenical® or Alli® (orlistat)
Examples of medications used to manage substance use disorders include:
Antabuse® (disulfiram)
Campral® (acamprosate)
Subutex® (buprenorphine)
Methadone
A medication called Contrave (naltrexone-bupropion) is FDA-approved to treat people with obesity or overweight plus a weight-related health condition. When used together with a reduced-calorie diet and regular exercise, this drug combination has been shown to help people lose weight.
Naltrexone can interact with other drugs, including:
Prescription opioids such as OxyContin® (oxycodone) or Vicodin® (hydrocodone)
Prescription cough medications that contain opioids, such as promethazine with codeine or Hydromet® (hydrocodone and homatropine)
Certain antidiarrheal medications that contain opioids, including Lomotil® (diphenoxylate and atropine) and Imodium-AD® (loperamide).
It’s a good idea to talk to your provider or pharmacist about any medications you’re taking before starting naltrexone.
Yes, constipation is among the possible side effects of naltrexone, although it typically resolves within a few weeks.
No, naltrexone is not addictive.
*This information is from the label for brand name Vivitrol®. See the Full Prescribing Information for more complete information. Naltrexone, the active ingredient in Vivitrol, may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient naltrexone.
Contrave. (2014). https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/200063s020lbl.pdf
Drugs.com. (n.d.). Naltrexone prices, coupons, copay cards & patient assistance. https://www.drugs.com/price-guide/naltrexone
Drugs.com. (n.d.). Vivitrol prices, coupons, copay cards & patient assistance. https://www.drugs.com/price-guide/vivitrol
National Library of Medicine. (2016). Acamprosate: MedlinePlus drug information. https://medlineplus.gov/druginfo/meds/a604028.html
National Library of Medicine. (2024). Buprenorphine sublingual and buccal (opioid dependence): MedlinePlus drug information. https://medlineplus.gov/druginfo/meds/a605002.html
National Library of Medicine. (2017). Disulfiram: MedlinePlus drug information. https://medlineplus.gov/druginfo/meds/a682602.html
National Library of Medicine. (2017). Naltrexone: MedlinePlus drug information. https://medlineplus.gov/druginfo/meds/a685041.html
Substance Abuse and Mental Health Services Administration. (2024). Substance Use Disorder Treatment Options. https://www.samhsa.gov/substance-use/treatment/options