Vivitrol (naltrexone extended release) is a brand-name drug that’s prescribed for alcohol dependence and opioid dependence in adults. Vivitrol comes as an intramuscular injection that’s given by a healthcare professional every 4 weeks.

Vivitrol is approved by the Food and Drug Administration (FDA) for use in adults to:

Vivitrol should be part of a complete treatment program that also includes support groups, counseling, and education.

Vivitrol belongs to a drug class called opioid antagonists. Vivitrol is not available in a generic version.

Keep reading for specific information about the dosage of Vivitrol, including its strength and how Vivitrol injections (shots) are given. For a comprehensive look at Vivitrol, see this article.

Note: This article describes typical dosages for Vivitrol provided by the drug’s manufacturer. However, your doctor will prescribe the dosage that’s right for you.

Before you start Vivitrol treatment, your doctor will discuss the best dosage for you. Be sure to tell your doctor about any other medical conditions you have or medications you take.

Vivitrol form

Vivitrol comes as a powder that’s mixed into a solution. A healthcare professional will give it as an intramuscular injection into your gluteal (buttock) muscle.

Vivitrol contains an extended-release form of naltrexone. Extended release means the drug is released over a period of time after you take it, instead of all at once.

Vivitrol strength

Vivitrol comes in one strength: 380 milligrams (mg) per 4 milliliters (mL) of solution.

Typical dosages

Your doctor will prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. They will determine the best dosage to fit your needs.

Dosage for alcohol dependence

The recommended dosage of Vivitrol for alcohol dependence is 380 mg given as an intramuscular injection once every 4 weeks. Your doctor or healthcare professional will inject the dose of Vivitrol into the muscle of your buttock.

Dosage for opioid dependence

The dosage of Vivitrol for opioid dependence is 380 mg given as an intramuscular injection once every 4 weeks. Your doctor or healthcare professional will inject the medication into the muscle of your buttock.

Before starting Vivitrol, you should not take any opioids for at least 7–10 days. This is to help prevent withdrawal symptoms, which can happen if you’ve recently taken opioids and then take Vivitrol.

Sometimes, withdrawal symptoms can be serious and may require hospitalization. It’s important to tell your doctor when you last took an opioid medication so that they can determine when you should start taking Vivitrol.

Long-term treatment

Vivitrol is meant to be used as a long-term treatment. If you and your doctor determine that Vivitrol is safe and effective for you, you’ll likely take it long term.

Accessible drug labels and containers

Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

You may have some questions about Vivitrol’s dosage before you start taking this medication. Below are some frequently asked questions. If you have additional questions about Vivitrol dosage, talk with your doctor before starting treatment.

Does Vivitrol come in an oral form, such as a pill? If so, what is the drug’s oral dosage?

Vivitrol does not come in an oral form. But naltrexone, Vivitrol’s active ingredient is available as an oral tablet.

Naltrexone tablets are not extended-release, which means that you need to take the drug every day for it to be effective. Vivitrol injections are extended-release, meaning the drug is released over a period of time instead of all at once.

Naltrexone tablets are approved to treat opioid or alcohol dependence. The dosage for naltrexone tablets is usually 50 mg taken by mouth once per day.

Naltrexone is a generic drug. A generic drug is an exact copy of the active drug in a brand-name medication. Vivitrol is the brand name for the injectable form of naltrexone.

If you’re interested in taking naltrexone tablets instead of Vivitrol injections, talk with your doctor. Sometimes, they may adjust your dose based on your specific treatment plan.

I’m switching from an oral drug to Vivitrol. How will my dosage change?

If you’re switching from an oral treatment to Vivitrol, your dosage may change. Be sure to talk with your doctor about the best way to switch from one medication to another. The best way to switch may depend on the medication you were taking before starting Vivitrol.

For example, if you’re taking oral naltrexone and would like to switch to Vivitrol, both drugs have the same active ingredient. Your dose will likely change from taking tablets once per day by mouth to receiving an intramuscular injection once per month from a healthcare professional.

If you’re switching from another treatment, such as buprenorphine, Suboxone (buprenorphine/naloxone), or methadone, your doctor will recommend the best way to switch to Vivitrol.

Sometimes, buprenorphine and buprenorphine/naloxone are taken more than once per day. If you switch to Vivitrol, you’ll only need an injection once per month.

Since Vivitrol is only injected once monthly, switching from an oral drug may help manage your opioid or alcohol dependence better. This is because you don’t have to worry about remembering to take your dose every day or even multiple times per day.

If you’re interested in switching from your oral drug to Vivitrol, talk with your doctor about how your dosage may change.

Vivitrol comes as a powder that’s mixed into a solution. A healthcare professional gives it as an intramuscular injection into the muscle of your buttock once every 4 weeks.

Your doctor or healthcare professional will alternate the injection site. If your first dose of Vivitrol is in your left buttock, your next dose will be in your right buttock. This is so you don’t develop scar tissue in the injection area.

If you have any questions about the dosage and administration of Vivitrol, talk with your doctor or pharmacist.

If you miss an appointment to receive a dose of Vivitrol, you should schedule an appointment as soon as you remember. It’s recommended that you receive your next dose of Vivitrol as soon as possible after a missed dose.

To help make sure you don’t miss a dose, try using a medication reminder. Medication reminders can help you remember your appointment for your Vivitrol injection. Reminders can include setting an alarm or using a timer. You could also download a reminder app on your phone.

Your doctor will determine the dosage of Vivitrol that you need. If you’re given too much Vivitrol, your doctor may recommend treatment for any symptoms you experience.

There’s limited information about Vivitrol overdose. Researchers have given a small number of people high doses of Vivitrol, and this didn’t lead to severe problems.

It’s important to note that your risk of opioid overdose may increase if you take opioids while you’re receiving Vivitrol treatment. You and your doctor should discuss this risk, and your doctor may recommend that you keep naloxone nasal spray (Narcan, Evzio) on hand. This drug can quickly reverse overdoses from opioids. In most states, you can get naloxone at a pharmacy without a prescription, or your doctor can prescribe it for you.

For more information, talk with your doctor or pharmacist. You can also see “Risk of opioid overdose” in the “Precautions” section of this article.

Symptoms of an overdose

Overdose symptoms of Vivitrol can include:

  • sleepiness
  • dizziness
  • injection site reaction
  • abdominal pain
  • nausea

If you receive more than the recommended amount of Vivitrol

Call your doctor right away if you believe you’ve received too much Vivitrol. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

If you have questions about your dosage of Vivitrol, talk with your doctor.

Besides learning about dosage, you may want other information about Vivitrol. These other articles might be helpful:

  • More about Vivitrol. For information about other aspects of Vivitrol, refer to this article.
  • Cost. For details about the cost of Vivitrol treatment, refer to this article.
  • Interactions. For information about possible interactions with Vivitrol, you can see this article.
  • Side effects. To learn about side effects Vivitrol can cause, see this article. You can also refer to the drug’s prescribing information.
  • Details about your condition. For details about dependence on alcohol or opioids, this list of articles may be helpful.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.