If you have a dependence on alcohol or opioids, your doctor might suggest Vivitrol as a treatment option. (With dependence, your body gets used to a substance and needs it for you to feel as you usually would.)

Vivitrol is a prescription drug used in adults to help:

  • treat alcohol dependence in those who have quit drinking and are not being treated in a hospital
  • prevent opioid dependence in those who have detoxed (had opioids cleared from their system)

A complete treatment program should include Vivitrol, education, counseling, and support groups.

The active ingredient in Vivitrol is naltrexone. (This is the ingredient that makes Vivitrol work.) It belongs to a group of drugs called opioid antagonists.

Vivitrol comes as an injection (shot) that’s given into a muscle of your buttocks by a healthcare professional.

This article describes the dosage of Vivitrol, as well as its strength and how it’s given. To learn more about Vivitrol, see this in-depth article.

Note: This chart highlights the basics of Vivitrol’s dosage. Be sure to read on for more detail. And keep in mind that this article covers Vivitrol’s standard dosing schedule, which is provided by the drug’s manufacturer. But your doctor will prescribe the Vivitrol dosage that’s right for you.

Vivitrol formVivitrol strengthVivitrol usual dosage
powder in a vial that is mixed with a liquid to make a solution380 milligrams (mg) per vial 380-mg injection every 4 weeks

The recommended dosage and dosing schedule for Vivitrol are described below.

What is Vivitrol’s form?

Vivitrol comes as a vial of powder that is mixed with a certain liquid to create a solution.

What strength does Vivitrol come in?

Vivitrol comes in one strength of 380 milligrams (mg) in a single-dose vial.

What is the usual dosage of Vivitrol?

Below is the most commonly recommended dosage of Vivitrol. But your doctor will determine the best dosage to fit your needs.

The recommended dosage of Vivitrol is one 380-mg injection about once per month. This is given by a healthcare professional.

Is Vivitrol prescribed long term?

Yes, Vivitrol is usually prescribed as a long-term treatment. If you and your doctor determine that Vivitrol is safe and effective for you, it’s likely you’ll receive it long term.

Some frequently asked questions about Vivitrol are answered below.

Does Vivitrol come in a form I can take orally (by mouth), such as a pill? If so, what’s the oral dosage?

No, Vivitrol doesn’t come as a pill or in any other oral form. It’s an injectable drug that’s given by a healthcare professional.

Naltrexone is the active drug in Vivitrol, and it comes as a tablet that you swallow. The recommended dosage of naltrexone tablets is 50 milligrams (mg) daily for opioid or alcohol dependence.

How long does Vivitrol take to work?

Vivitrol usually starts to work about 2 hours after your injection. The drug continues to work in your body until your next dose 4 weeks later. The levels of Vivitrol in your blood begin to slowly drop about 2 weeks after your injection.

Will my dose be different depending on how much I weigh?

No, your Vivitrol dose is not based on your weight. But your body size will determine the size of the needle used to give you your injection. The manufacturer of Vivitrol supplies needles of different sizes with each vial. This is to be sure the drug reaches into your muscle.

You’ll receive your dose of Vivitrol from a healthcare professional. Right before you receive your dose, they’ll mix the medication into a liquid solution and inject it into a muscle of your buttocks. You’ll receive a dose about once each month.

If you miss a Vivitrol injection appointment, contact your doctor right away to reschedule. It’s important to follow your dosing schedule to keep the right level of the drug in your body.

If you need help remembering your Vivitrol appointments, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

Vivitrol itself does not cause withdrawal or dependence. But opioid withdrawal can happen while you’re receiving Vivitrol if opioids are still in your system.

Before starting Vivitrol, you must stop taking any opioids. Sudden opioid withdrawal can occur if you receive a dose of Vivitrol and have also taken an opioid within 7 to 14 days.

You may also be more sensitive to opioids during or after treatment with Vivitrol. Your risk of opioid overdose can increase if you take any amount of opioids while being treated with Vivitrol. Opioid overdose and withdrawal are medical emergencies and can be life threatening.

Your doctor will determine the correct dosage of Vivitrol for you. There are limited data about overdose with Vivitrol. High doses did not lead to serious problems but did cause some symptoms.

If an overdose of Vivitrol occurs, your doctor will determine whether you need treatment for any symptoms.

It’s important to note that your risk of opioid overdose may increase if you take opioids while you’re receiving Vivitrol treatment (see “Vivitrol dependence and withdrawal” just above for details).

Symptoms of overdose

Symptoms caused by an overdose can include:

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

What to do in case you receive too much Vivitrol

Call your doctor right away if you think you’ve received too much Vivitrol. You can also call 800-222-1222 to reach the American Association of Poison Control Centers or use its online resource. But if you have severe symptoms, call 911 (or your local emergency number) immediately or go to the nearest emergency room.

The sections above describe the usual dosage provided by the drug’s manufacturer. If your doctor recommends Vivitrol for you, they’ll prescribe the dosage that’s right for you.

Here are some examples of questions you may want to ask your doctor:

  • Will my dosage of Vivitrol be different if I have liver problems?
  • Will my doctor change my dose of Vivitrol if I continue to have alcohol or opioid cravings?
  • Is the dosage of Vivitrol different if I’m switching from oral naltrexone to Vivitrol injections?

Talk with your doctor if you have questions or concerns about your current dosage.


Is the dosage of Vivitrol different if it’s prescribed for alcohol dependence as opposed to preventing a recurrence of opioid dependence?



No, the dosage of Vivitrol is the same for the treatment of alcohol dependence and for the prevention of a recurrence of opioid dependence. The recommended dosage is 380 milligrams (mg) about once per month.

In studies, the same 380-mg dose was given to people with either opioid or alcohol dependence. Opioid and alcohol dependence involve the same system that controls reward, pain, and addiction in your body. Vivitrol works by blocking the effects of opioids. Exactly how Vivitrol works to treat alcohol dependence isn’t known for certain.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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