What Is Vivitrol? How Does Naltrexone Vivitrol Work?

Vivitrol is a formula of naltrexone that is injected intramuscularly and lasts for one month. This medication was originally used for treating alcohol use disorder. It is still used for alcohol, but now it is increasingly also being used to help prevent craving and relapse for people overcoming opioid use disorder. It is one of three primary medications used for the treatment of opioid use disorder, or Medications for Addiction Treatment (MAT). 

In addition to reducing cravings and preventing relapse, naltrexone also blocks the effects of opioids on the opioid receptors in the brain. Therefore, in the event of a relapse, the person will not become intoxicated, will not experience euphoria, and will be much less likely to overdose. However, if you take Vivitrol before all the opioids are out of your system, including buprenorphine (which is a partial agonist), you might experience what is called “precipitated withdrawal”, when naltrexone kicks the opioids out of the opioid receptors in your brain.

Vivitrol: A Helpful Naltrexone Formula

Medication for Addiction Treatment (MAT) helps people overcome some substance use disorders, like alcohol or opioid use disorder. It reduces cravings, and helps people focus away from drug use and towardson counseling and other important rehabilitation-promoting activities.

In particular, people overcoming opioid use disorder (OUD) benefit from prescription medications that can help them maintain abstinence from highly addictive drugs like heroin or fentanyl. Although most treatment programs start with buprenorphine-based medications like Suboxone, you may be better suited for naltrexone. You and your doctor can decide together which medication is best for you.

Unlike buprenorphine, naltrexone is an opioid antagonist.[1] This medication eases cravings for alcohol or opioids. As a result of its antagonist activity, it also binds to receptors in the brain to stop opioids from causing intoxication, euphoria, and overdose.

There are several brand names of naltrexone, and one of the most effective is Vivitrol.[2]

How Does Vivitrol Work?

Vivitrol is an extended-release intramuscular injection with naltrexone as its active ingredient.[3] Vivitrol remains in the body for up to one month, slowly releasing naltrexone into the bloodstream from the injection site, so that people don’t have to take a pill every day. 

Recall that vivitrol stops opioids from binding to the opioid receptors in the brain.[4] In the event of a relapse on illicit opioids like heroin or fentanyl, if naltrexone is already   present in the body, it will block the opioids from activating the opioid receptors in the brain. This makes it a great option for people who continue to use opioids but are willing to take MAT, as it greatly reduces the overdose risk. Vivitrol has another positive benefit other than preventing overdose and death for people who struggle with repeated relapses. By blocking the euphoria and high, people taking Vivitrol for OUD stop associating feeling good with the behavior of using, and the using habit wanes.

Just after a Vivitrol injection, there is a slight peak in the amount of naltrexone in the bloodstream, which occurs after about two hours. A second peak has been observed about two to three days later. After 14 days, naltrexone levels begin to decline, with less efficacy after about a month, which is when the next injection is due. Vivitrol’s half-life is about 5 to 10 days. 

If you think you might benefit from Vivitrol, it is important to taper off any buprenorphine-based medications or other opioids first since naltrexone will kick these off the opioid receptors and trigger withdrawal.[5] Symptoms of opioid withdrawal include the following:

• Anxiety, restlessness, and irritability
• Insomnia
• Runny nose
• Goosebumps
• Watering eyes
• Sweating
• Excessive yawning
• Fever
• Muscle aches and cramps
• Nausea, vomiting, and stomach upset
• Diarrhea
• Joint pain

If you experience any symptoms of withdrawal after starting Vivitrol, you might still have other opioids or buprenorphine in your system. Talk to your provider and they can help you determine next steps.

Potential Vivitrol Side Effects

‍You might feel some side effects at the injection site, including these:

• Pain
• An area of the skin that feels hard
• Swelling at or near the site
• Lumps
• Blisters
• Open wounds
• A dark scab
• Infection

These are very rare side effects, but if you do experience them, contact your physician for help.

Naltrexone might cause liver damage, especially in people who already have some liver damage from opioids or alcohol. Liver damage can cause jaundice, which has symptoms like these:

• Stomach pain that lasts more than a few days
• Dark urine
• Yellowing eyes or skin
• Fatigue

If you have liver damage, hepatitis, or are concerned about liver damage, discuss this with your doctor before beginning Vivitrol treatment.

It is still possible to overdose on opioids while taking Vivitrol. In the event of a relapse, Vivitrol will stop the person from feeling intoxicated, but opioids can still overwhelm the body and cause breathing problems, coma, and death.

Where Can You Get Vivitrol?

Vivitrol was one of the first extended-release treatments for OUDs approved by the U.S. Food and Drug Administration (FDA).[6] While many people benefit from Vivitrol to help them manage abstinence, initiating is challenging, as you may need many days of no opioid in your system before you can start it safely.

Once you are opioid-free, it is easier to start Vivitrol without risk of withdrawal. Steps include the following:[7]

• Find a Vivitrol provider, which might be your local pharmacy or a specialist.
• Complete the pharmacy form and the Specialty Pharmacy Form.
• Verify Vivitrol is covered by insurance and discuss the Vivitrol Co-Pay Savings Program, available through the pharmaceutical company.
• Confirm shipping and delivery information.
• Keep your Vivitrol appointments once per month.

Without insurance or copay assistance, one 380 mg dose of Vivitrol costs $1,487.06 in 2022.[8] Fortunately, insurance increasingly covers MAT including naltrexone, and copay programs can help you offset the costs of the first few doses.