What is the status of Vivitrol (naltrexone) in the United States?

From the Guidelines

Vivitrol is a recommended treatment option for patients with opioid dependence in the United States, as it has been shown to be effective in preventing relapse and reducing cravings, according to the most recent and highest quality study 1.

Key Points to Consider

• Vivitrol (naltrexone for extended-release injectable suspension) is an FDA-approved medication used in the United States for treating alcohol dependence and preventing relapse to opioid dependence after detoxification.
• The medication works by blocking opioid receptors in the brain, reducing cravings and the pleasurable effects of alcohol or opioids.
• Common side effects include injection site reactions, nausea, headache, and fatigue.
• Liver function should be monitored during treatment as naltrexone can cause hepatotoxicity.
• Vivitrol is typically used as part of a comprehensive treatment program that includes counseling and psychosocial support.

Administration and Monitoring

• Vivitrol is administered as a monthly intramuscular injection of 380 mg into the gluteal muscle, alternating buttocks for each subsequent injection.
• Before starting Vivitrol, patients must be opioid-free for 7-10 days to avoid precipitating withdrawal.
• Treatment duration varies based on individual needs, but many patients remain on Vivitrol for at least 6-12 months.

Insurance Coverage and Accessibility

• Insurance coverage for Vivitrol has improved in recent years, though prior authorization may be required.
• The American College of Physicians recommends lifting barriers that impede access to medications to treat opioid use disorder, including naltrexone, and expanding access to medication-assisted treatment 1.

Evidence-Based Practice

• The effectiveness of Vivitrol stems from its ability to reduce reward pathways associated with substance use while its monthly administration helps address medication adherence challenges common in addiction treatment.
• Studies have shown that medication-assisted treatment, including naltrexone, can be effective in treating opioid use disorders in adolescents and young adults 1.

From the FDA Drug Label

Hepatic and Renal Impairment Naltrexone appears to have extra-hepatic sites of drug metabolism and its major metabolite undergoes active tubular secretion The efficacy of naltrexone hydrochloride as an aid to the treatment of alcoholism was tested in placebo-controlled, outpatient, double blind trials. Naltrexone hydrochloride has been shown to produce complete blockade of the euphoric effects of opioids in both volunteer and addict populations.

The drug Vivitrol (naltrexone) is used in the United States for the treatment of:

• Alcoholism: as an aid to the treatment of alcoholism
• Opioid Addiction: to produce complete blockade of the euphoric effects of opioids 2 Key points:
• Naltrexone hydrochloride does not lead to physical or psychological dependence 2
• It is contraindicated in patients receiving opioid analgesics, patients currently dependent on opioids, and patients in acute opioid withdrawal 2

From the Research

Vivitrol in the United States

• Vivitrol, also known as extended-release intramuscular naltrexone (XR-NTX), is a μ-opioid receptor antagonist that blocks the euphoric effects of heroin and prescription opioids 3.
• It is approved in the USA for the prevention of relapse to opioid dependence, after opioid detoxification 3, 4.
• The clinical efficacy of XR-NTX in patients with opioid dependence was demonstrated in a 24-week, randomized, double-blind, placebo-controlled, multicentre, phase III trial, which showed that XR-NTX was associated with a significantly higher median proportion of weeks of confirmed opioid abstinence, a significantly higher proportion of patients achieving total confirmed abstinence, a significantly greater reduction in opioid craving, and a significantly longer treatment retention period than placebo 3.
• XR-NTX was generally well tolerated in the phase III trial, with the most common treatment-emergent adverse events being hepatic enzyme abnormalities, nasopharyngitis, insomnia, hypertension, influenza, and injection-site pain 3.
• A study comparing XR-NTX with sublingual buprenorphine-naloxone found that patients who reported being homeless had a lower relapse rate if they were assigned to receive XR-NTX, while patients who were not homeless had a higher relapse rate if they were assigned to XR-NTX 5.
• Another study found that sublingual buprenorphine-naloxone might be more effective than XR-NTX in preventing relapse in opiate use disorder, with a significantly higher abstinence time observed in the buprenorphine-naloxone group 6.

Mechanism of Action

• Naltrexone is a μ-opioid receptor antagonist that blocks the euphoric effects of heroin and prescription opioids 3.
• The combination of buprenorphine and naltrexone may counteract the dysfunction of the opioid system with kappa receptors hyper-activation provoked by heroin exposure, which can lead to dysphoric and psychosomatic symptoms during naltrexone treatment 7.

Safety and Tolerability

• XR-NTX was generally well tolerated in the phase III trial, with the most common treatment-emergent adverse events being hepatic enzyme abnormalities, nasopharyngitis, insomnia, hypertension, influenza, and injection-site pain 3.
• Liver function tests were within the normal ranges at the three time points, which were just before the beginning and in the first and third months of treatment, in a study comparing XR-NTX with sublingual buprenorphine-naloxone 6.