Extended-release naltrexone injection is a once-monthly prescription medication used in the treatment of opioid use disorder and alcohol use disorder. This article explains how the medication works, who may be appropriate for it, how injections are given, common benefits and limitations, and important safety considerations. Placement and medication choices always require assessment by a qualified clinician familiar with the persons medical history and treatment goals.

What is extended-release naltrexone injection?

Extended-release naltrexone, sold as VIVITROL and generics, is a medication consisting of naltrexone in a long-acting injectable formulation given by intramuscular gluteal injection every 4 weeks. Naltrexone is an opioid receptor antagonist, meaning it blocks opioid effects at the receptor level and can reduce the reinforcing effects of opioid use and reduce alcohol craving in people with alcohol use disorder. The injection formulation provides sustained blood levels for about a month after each dose. (accessdata.fda.gov)

Who may be considered for this medication?

Extended-release naltrexone injection may be offered to adults with opioid use disorder or alcohol use disorder when a clinician and patient agree it fits the patients needs and goals. It is often considered when a patient prefers an opioid-free treatment approach, when adherence to daily oral medications is unlikely, or when there is concern about diversion of opioid-agonist medications. Clinical guidelines recommend offering medication treatment for opioid use disorder and selecting the medication that best fits the persons medical profile and choices. (asam.org)

Important exclusions and cautions

  • Do not start the injection in someone who is currently dependent on or taking opioid medications: giving naltrexone to a person with opioids in their system can precipitate sudden, severe opioid withdrawal. Most clinicians require at least 7 to 14 days opioid-free, depending on the opioid type, before the first dose. (nida.nih.gov)
  • People with acute hepatitis or liver failure should not receive extended-release naltrexone because of the potential for liver injury; baseline and periodic liver tests are recommended. (accessdata.fda.gov)
  • Because naltrexone blocks opioid effects, it changes how acute pain is managed. Elective surgeries and severe acute pain require planning between the patient, addiction clinician, and surgical or emergency team. (cdc.gov)

How extended-release naltrexone injection is used in treatment

Typical steps for initiation and ongoing use include medical assessment, screening for recent opioid use, explanation of benefits and risks, and arranging follow-up and psychosocial supports. Clinicians use urine testing, treatment history, and clinical examination to confirm a patient is opioid-free before the first injection. Standard dosing for the commercially available preparation is 380 mg intramuscularly every 28 to 30 days. (accessdata.fda.gov)

Combining medication with counseling and supports

Medication is most effective when combined with counseling, case management, and social supports. Clinical guidelines emphasize offering psychosocial interventions and linkage to community resources alongside medication. Discuss options for counseling, peer support, and contingency planning with your care team. (asam.org)

Benefits and limitations

Potential benefits include a once-monthly administration that removes the need for daily pills, reduced opioid reward if the person returns to opioid use, and usefulness for people who prefer an antagonist-based, opioid-free approach. Randomized trials show extended-release naltrexone reduces relapse versus placebo and can produce similar short-term outcomes to buprenorphine in some study settings, when patients can be successfully inducted. (pmc.ncbi.nlm.nih.gov)

Limitations include the need to be opioid-free before the first injection, which can make induction harder than starting buprenorphine or methadone. Some trials found more early dropouts during induction with naltrexone. Also, because opioid tolerance decreases during antagonist treatment, the risk of fatal overdose is increased if a person stops naltrexone and returns to previous opioid doses. Clinicians should discuss this risk and provide overdose-response planning. (pmc.ncbi.nlm.nih.gov)

Safety, monitoring, and pain care

Common side effects include injection-site reactions, nausea, headache, and sleep disturbance. Rare but important risks include liver injury and allergic reactions. Baseline liver tests are typically obtained and monitored during treatment. Patients should be advised to seek medical attention for symptoms of liver injury such as abdominal pain, persistent nausea, dark urine, or jaundice. (accessdata.fda.gov)

Pain care and emergency opioid use: Because naltrexone blocks opioid analgesics, clinicians should plan ahead for dental care, surgery, or acute traumatic pain. When opioid analgesia is unavoidable, clinicians experienced in pain and addiction management should be involved; in practice non-opioid strategies and regional anesthesia are preferred when feasible. Patients and family should be given an opioid overdose rescue kit (naloxone) and trained in its use. (cdc.gov)

Medication How it works Typical dosing Key advantages Main limitations
Extended-release naltrexone injection Opioid antagonist, blocks opioid effects 380 mg IM every 28-30 days Once-monthly, no opioid agonist on board, low diversion risk Requires opioid-free period before start, possible liver effects, overdose risk if stopped
Buprenorphine (sublingual or buccal) Partial opioid agonist, reduces cravings and withdrawal Daily dosing or long-acting implants/injections available Can be started with mild-moderate withdrawal, strong evidence for reducing mortality Daily dosing for some forms, potential for diversion
Methadone Full opioid agonist, reduces withdrawal and cravings Daily supervised dosing, individualized titration Extensive evidence for retaining patients and reducing overdose Requires clinic dosing for many patients, regulated by law

Note: Choosing medication depends on medical history, treatment goals, access, and patient preference. Talk with a clinician about which option fits you best. (asam.org)

One-page comparison and decision quick-check

Use this short checklist as a discussion starter with your clinician:

  • Do you want an opioid-free treatment approach? If yes, extended-release naltrexone may be an option once you are opioid-free. (samhsa.gov)
  • Do you have trouble with daily medication adherence? Once-monthly injection can help with adherence problems. (accessdata.fda.gov)
  • Are you currently taking prescription opioids or physically dependent on opioids? If yes, naltrexone should not be started until you are opioid-free and cleared by a clinician. (nida.nih.gov)
  • Do you have severe liver disease? Discuss alternative medications because naltrexone can affect liver enzymes. (accessdata.fda.gov)

Safety callout: For a medical emergency call 911. If you or someone is in a mental health or suicide crisis, call or text 988 to reach the Suicide & Crisis Lifeline. If you are in danger of opioid overdose, give naloxone if available and call 911 immediately. Always tell emergency staff about recent naltrexone doses because they affect opioid response.

Frequently asked questions

Will the injection make me unable to feel pain?

No. Naltrexone blocks opioid effects but does not eliminate other pain pathways. It will reduce the effect of opioid pain medicines, so non-opioid pain strategies and careful planning with clinicians are needed for surgeries or severe injuries. (pmc.ncbi.nlm.nih.gov)

How long does protection against opioids last after an injection?

The medication is detectable and pharmacologically active for about one month, but exact duration varies. Stopping injections reduces blockade over days to weeks, and opioid tolerance may fall, increasing overdose risk if opioids are resumed. Clinicians will discuss overdose prevention and provide naloxone. (accessdata.fda.gov)

Does insurance in New Jersey cover VIVITROL?

Coverage varies by insurer and plan. New Jersey state programs and many commercial plans cover medications for opioid use disorder, and state initiatives support access to all FDA-approved medications. Check your plan, and your treatment provider can help with prior authorization and benefit verification. For state resources and treatment directories in New Jersey see the Division of Mental Health and Addiction Services. (law.justia.com)

Next steps and how we can help

This article is general education, not individualized medical advice. Medication decisions require a confidential medical assessment with a qualified prescriber who will review your medical history, current medications, and treatment goals. If you are near one of our New Jersey outpatient locations, we can discuss whether extended-release naltrexone injection may fit your plan, and outline induction, monitoring, and counseling supports. Learn about our treatments and programs, find a location, or contact us for an assessment: treatments, locations, contact us.

Final invitation: If you want a confidential assessment or to speak with an admissions team member, please request an assessment or call our clinic. We will meet you where you are, explain options without pressure, and help arrange the next steps with your safety in mind.

Sources and further reading

If you are in immediate danger call 911. For mental health crisis or suicide risk call or text 988. For questions about treatment options, insurance, or to arrange a confidential assessment please contact us.