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Vivitrol: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Jun 10, 2020.

1. How it works

  • Vivitrol is a brand (trade) name for naltrexone injection. How naltrexone works in alcoholism is not completely understood; however, some experts believe it works by blocking the effects of naturally occurring opioids (such as endorphins).
  • Do not confuse naltrexone with naloxone (Narcan), which strips the opioid from the opioid receptor and is used for the emergency treatment of opioid overdose.
  • Vivitrol belongs to a class of medicines called opioid antagonists.

2. Upsides

  • Vivitrol may be used to treat alcohol dependence in patients who are able to abstain from alcohol in an outpatient setting prior to the initiation of Vivitrol. Patients should not be actively drinking at the time of initial Vivitrol administration.
  • Vivitrol has also been shown to improve abstention rates, reduce the number of drinking days, and reduce the risk of relapse. It also reduces alcohol cravings.
  • Vivitrol does not cause physical or psychological dependence and is not considered a drug of abuse. Tolerance to Vivitrol's effect does not appear to occur.
  • Apart from its opioid blocking effects and some pupillary constriction (a decrease in the size of the pupil of the eye), Vivitrol has few, if any, other reported effects.
  • Vivitrol is an extended-release IM injectable preparation.
  • Pretreatment with oral naltrexone is not required before using Vivitrol.
  • Vivitrol is given by intramuscular injection once a month (or every 4 weeks).

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Nausea, a headache, depression, fatigue, insomnia, anxiety, and sleepiness are the most common side effects reported. Generally, Vivitrol is well-tolerated in people who are genuinely opioid-free.
  • Vivitrol is not aversive therapy and does not cause any specific reactions when combined with opioids or alcohol; however, it may precipitate withdrawal symptoms when used with opioids, and these may be severe enough to warrant hospitalization. Use of Vivitrol does not diminish or eliminate opioid withdrawal symptoms. A naltrexone challenge test may need to be performed if there is any suspicion of opioid dependence.
  • People who are dependent on opiate drugs should stop taking the opioid seven to fourteen days prior to starting Vivitrol. Treatment with Vivitrol should not be attempted otherwise.
  • Avoid in people currently using opioids, with certain types of liver disease or with chronic pain who rely on opioid painkillers.
  • May not be suitable for people with kidney disease, liver disease, receiving or dependent on opioid analgesics. May cause hepatitis or significant liver dysfunction.
  • Requires good compliance to be effective. May increase vulnerability to opioids once the detoxification process is complete, which means a lower dose of opioid may cause life-threatening intoxication.
  • Does not affect the use of cocaine or other non-opioid drugs of abuse.
  • Vivitrol should only be given as part of a well-managed alcohol abuse management plan.
  • Vivitrol must be administered by a health care professional.

Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.

4. Bottom Line

Vivitrol is used as an adjunct to social and psychotherapy in the treatment of alcohol addiction that is given by intramuscular injection by a health professional once every four weeks. People taking Vivitrol need to have completely stopped drinking before being administered Vivitrol and have stopped taking all types of opioids a minimum of seven to fourteen days prior.

5. Tips

  • Vivitrol should be used in addition to comprehensive social and psychotherapeutic measures to reduce opioid or alcohol addiction.
  • Always carry identification that alerts medical personnel to the fact you are taking Vivitrol. A Vivitrol medication card is available from most treatment centers for this purpose.
  • If you try and self-administer opioids while taking Vivitrol, you will not perceive any effect.
  • Stop Vivitrol and see your doctor immediately if you develop abdominal pain lasting more than a few days, white bowel movements, dark urine, or yellowing of your eyes.
  • Talk to your doctor or pharmacist before self-administering any cough or cold remedies or pain-relieving treatments because some of these may contain codeine or other opioid-like ingredients that may interact with Vivitrol.
  • Vivitrol may affect your ability to drive or operate machinery. Do not perform any kind of hazardous task if Vivitrol affects you like this.
  • Vivitrol should be administered by a health care professional as an intramuscular injection, in alternating buttocks, every month or 4 weeks.

6. Response and Effectiveness

  • Peak plasma levels of naltrexone, the active component of Vivitrol, reach a transient initial peak approximately two hours after injection, followed by a second peak that occurs two to three days later. Blood levels of naltrexone slowly start to decline after 14 days with measurable levels continuing for about a month.
  • Compared to oral naltrexone 50mg given daily, total naltrexone exposure is three to four-fold higher after a single dose of Vivitrol 380mg IM.

7. Interactions

Medicines that interact with Vivitrol may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Vivitrol. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Vivitrol include:

  • disulfiram, used in the management of alcohol abuse
  • all medications that have sedation as a side effect, including antidepressants, first-generation antihistamines, antipsychotics, anti-anxiety medications
  • any medication that also contains an opioid, such as codeine, hydrocodone, loperamide, methadone, morphine, or oxycodone. This includes pain relievers, anti-diarrheal medications, or cough and cold preparations.

Avoid drinking alcohol or taking illegal or recreational drugs while taking Vivitrol.

Note that this list is not all-inclusive and includes only common medications that may interact with Vivitrol. You should refer to the prescribing information for Vivitrol for a complete list of interactions.


Vivitrol (naltrexone injection) [Package Insert]. 12/2019. Alkermes, Inc.

Further information

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

Copyright 1996-2020 Revision date: June 10, 2020.

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