What Is Vivitrol? Uses, Side Effects, and What to Expect

Key Takeaways

• Vivitrol is the brand name for extended-release injectable naltrexone, a monthly injection used to treat opioid and alcohol use disorders
• It works by blocking opioid receptors for approximately 30 days, reducing cravings and preventing the euphoric effects of opioids or alcohol
• Patients must be fully detoxed from opioids for 7 to 14 days before starting Vivitrol to avoid precipitated withdrawal
• Common side effects include nausea, injection site reactions, headache, and fatigue
• Vivitrol is FDA-approved for both opioid use disorder and alcohol use disorder, making it one of the few medications indicated for both conditions

Vivitrol: The brand name for extended-release injectable naltrexone, manufactured by Alkermes. It is administered as a monthly intramuscular injection that blocks opioid receptors for approximately 30 days, used as part of medication-assisted treatment for opioid and alcohol use disorders.

Vivitrol is a once-monthly injection that helps people in recovery from opioid or alcohol addiction maintain abstinence by blocking the brain’s opioid receptors. Its active ingredient, naltrexone, is an opioid antagonist that prevents opioids from producing euphoric effects and reduces alcohol cravings through modulation of the brain’s endogenous opioid system. The extended-release formulation means the medication is delivered continuously from a single injection, eliminating the need for daily medication adherence — a significant advantage for patients who struggle with daily pill regimens.

What Vivitrol Is and How It Works

Extended-Release Naltrexone Explained

Extended-Release Formulation: A drug delivery system designed to release medication gradually over an extended period, maintaining therapeutic levels in the body without requiring frequent dosing. Vivitrol uses a polymer microsphere technology that slowly releases naltrexone over approximately 30 days.

Vivitrol contains 380 mg of naltrexone suspended in a biodegradable polymer matrix. When injected into the gluteal muscle, the polymer microspheres gradually break down, releasing naltrexone into the bloodstream at a consistent rate. This sustained release maintains therapeutic blood levels of naltrexone for roughly four weeks, after which the next injection is due.

Oral naltrexone (brand name ReVia) has been available since 1984, but adherence rates were historically poor — many patients simply stopped taking their daily pill. The extended-release injectable formulation was developed specifically to address this compliance problem. The FDA approved Vivitrol for alcohol use disorder in 2006 and for opioid use disorder in 2010.

How the Monthly Injection Blocks Cravings

Naltrexone occupies opioid receptors without activating them. With those receptors blocked:

• For opioid use disorder — if a person uses heroin, fentanyl, or prescription opioids while on Vivitrol, they will not experience the expected euphoric or sedating effects. This removes a primary reinforcement mechanism for continued use.
• For alcohol use disorder — naltrexone modulates the endogenous opioid system, which plays a role in the rewarding effects of alcohol. Patients on naltrexone typically report that alcohol produces less pleasure, making it easier to reduce or stop drinking.

The blocking effect is not absolute willpower — it is a pharmacological intervention that changes the brain’s response to substances, providing a neurochemical foundation on which behavioral therapy and recovery support can build.

What Vivitrol Is Used to Treat

Opioid Use Disorder

Vivitrol is one of three FDA-approved medications for opioid use disorder (OUD), alongside buprenorphine (Suboxone, Sublocade) and methadone. It occupies a distinct position among these options because it is a pure antagonist — it does not activate opioid receptors at all, unlike buprenorphine (a partial agonist) or methadone (a full agonist).

Opioid Use Disorder (OUD): A chronic medical condition defined by the DSM-5 as a problematic pattern of opioid use leading to clinically significant impairment or distress, characterized by cravings, tolerance, withdrawal, and continued use despite negative consequences.

The critical prerequisite for starting Vivitrol in OUD patients is complete opioid detoxification. The patient must be opioid-free for a minimum of 7 to 14 days before the first injection. If naltrexone is administered while opioids are still occupying receptors, it precipitates severe withdrawal — a sudden onset of intense withdrawal symptoms caused by the abrupt displacement of opioids from receptors.

Alcohol Use Disorder

Vivitrol’s FDA approval for alcohol use disorder preceded its opioid indication. For patients with alcohol use disorder, the medication does not require a detox waiting period (though medical alcohol detox should be completed for safety reasons). Naltrexone reduces the rewarding effects of alcohol by interfering with the endorphin release that drinking triggers.

Alcohol Use Disorder (AUD): A medical condition characterized by an impaired ability to stop or control alcohol use despite adverse social, occupational, or health consequences. The National Institute on Alcohol Abuse and Alcoholism (NIAAA) estimates that approximately 29.5 million Americans ages 12 and older had AUD in 2021.

Vivitrol is not a “cure” for alcohol use disorder. It is most effective when used as one component of a comprehensive treatment plan that includes counseling, behavioral therapy, and peer support.

Common Side Effects and Risks

Injection Site Reactions

The most frequently reported side effect of Vivitrol is a reaction at the injection site. This can include:

• Pain, tenderness, or hardness at the injection area
• Swelling or redness
• A lump or nodule that may persist for several weeks

In rare cases, injection site reactions can be severe, including tissue death (necrosis) that requires surgical intervention. Patients should report any worsening pain, swelling, or skin changes at the injection site to their healthcare provider promptly.

Other Side Effects

According to the prescribing information and clinical trial data, other common side effects include:

• Nausea (reported in approximately 33% of patients in clinical trials)
• Headache
• Fatigue and drowsiness
• Dizziness
• Decreased appetite
• Joint pain
• Muscle cramps
• Insomnia or sleep disturbances

Most side effects are most prominent after the first injection and tend to diminish with subsequent doses.

Serious Warnings

Hepatotoxicity: The potential for a medication to cause liver damage. Naltrexone carries an FDA boxed warning regarding the risk of liver injury, though this risk appears to be dose-dependent and is primarily associated with doses higher than those used in standard treatment.

Vivitrol’s prescribing information includes several serious warnings:

• Liver injury risk — naltrexone can cause liver enzyme elevations. Patients with pre-existing liver disease require monitoring. The medication is contraindicated in acute hepatitis or liver failure.
• Overdose vulnerability — after Vivitrol wears off or if a patient discontinues treatment, their opioid tolerance is reduced. Attempting to use opioids at previously tolerated doses can result in fatal overdose. This is one of the most critical safety considerations.
• Precipitated withdrawal — administering Vivitrol to a patient who has not fully detoxed from opioids causes sudden, severe withdrawal.
• Depression and suicidality — some patients have reported depressed mood. Patients and families should be alert to mood changes.

What to Expect During Vivitrol Treatment

Before Your First Injection

Before initiating Vivitrol, providers typically:

1. Confirm the patient has completed opioid detoxification (7-14 days opioid-free) through urine drug screening and clinical assessment
2. Conduct liver function tests to establish a baseline
3. Perform a naloxone challenge test in some cases — a small dose of naloxone is administered to check for precipitated withdrawal before giving the longer-acting naltrexone
4. Review the patient’s medical history for contraindications including pregnancy, liver disease, or current opioid use

Monthly Treatment Schedule

After the first injection, the treatment protocol is straightforward:

• Return to the provider’s office every four weeks (approximately 28 days) for the next injection
• The injection is administered in the gluteal muscle by a healthcare professional
• A brief monitoring period follows each injection to observe for allergic reactions
• Ongoing liver function tests may be ordered periodically
• Behavioral therapy and counseling continue alongside the medication

Treatment duration varies. SAMHSA recommends that medication for opioid use disorder be continued for as long as the patient benefits from it, with no predetermined endpoint. Some patients remain on Vivitrol for months; others continue for years.

Accessing Vivitrol Treatment in NJ

Finding Vivitrol Providers

Vivitrol must be administered by a healthcare provider — it is not a self-administered medication. In New Jersey, Vivitrol is available through:

• Addiction medicine practices and outpatient treatment programs
• Opioid treatment programs (OTPs) that offer antagonist-based treatment
• Some primary care practices with providers trained in addiction medicine
• Hospital-based addiction treatment programs

SAMHSA’s treatment locator (findtreatment.gov) allows users to filter for providers offering naltrexone, including Vivitrol. The New Jersey Division of Mental Health and Addiction Services (DMHAS) also maintains referral resources.

Insurance Coverage and Cost

Without insurance, a single Vivitrol injection costs approximately $1,000 to $1,800, making it one of the more expensive MAT options. However, most insurance plans cover Vivitrol:

• Private insurance — the Mental Health Parity and Addiction Equity Act requires most plans to cover SUD treatment, including MAT medications
• NJ Medicaid — covers Vivitrol for qualifying patients
• Medicare — covers Vivitrol under Part B (administered in a provider’s office)
• Alkermes patient assistance — the manufacturer offers co-pay assistance programs and a patient assistance program for uninsured patients

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This glossary entry is part of our Addiction Treatment Glossary. For a comparison of Vivitrol with other MAT medications, see Vivitrol vs. Suboxone vs. Sublocade. For practical logistics including cost details and storage, read The Vivitrol Program: Cost, Refrigeration, and Practical Details. To learn about MAT as a broader treatment approach, visit our guide to medication-assisted treatment or explore insurance coverage for rehab.