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How Long Does Vivitrol Last?

If you are interested in learning more about whether Vivitrol is a good choice for you or your loved one, contact your doctor or treatment team. Vivitrol is only available through a healthcare provider and with a prescription. Medical supervision throughout treatment is recommended, as are therapeutic interventions that work with the medication to create a well-rounded addiction treatment program.[3]

Struggling with Addiction? Get Help Now

Vivitrol, or naltrexone, is a medication that is designed to assist people in recovery from alcohol addiction or opioid addiction. The medication can help users to manage their relapse risk, and they don’t have to worry about taking a daily medication since Vivitrol’s effects last for a month.[1]

Because it is a monthly injection, Vivitrol helps people get the benefits of medication-assisted treatment (MAT) when they live far from the doctor or otherwise have a hard time accessing or remembering to take a daily medication. 

A single shot is designed to be effective in the body for anywhere from 28 to 30 days.[2] The medication is slowly released into the system over the course of the month to maintain a therapeutic level of naltrexone in the body that blocks the opioid receptors on an ongoing basis. 

Understanding How Vivitrol Shots Work

Vivitrol shots work a little differently than other drugs that are designed to help people in recovery from alcohol use disorder (AUD) or opioid use disorder (OUD). A few different actions take place simultaneously to help the person avoid relapse. Here’s how Vivitrol works:

Binds to Opioid Receptors

Naltrexone, the active ingredient in Vivitrol, is an opioid antagonist, which means that it works by binding to opioid receptors in the brain.[4] This serves to block the effects of opioids if ingested while on the drug, stopping the person from getting high if they relapse. 

The mechanism by which Vivitrol works to reduce alcohol consumption isn’t entirely understood, but studies show it is effective for this purpose.[14]

Extended-Release Formulation

Vivitrol is given to the patient one time each month in the form of an intramuscular injection, providing the person with one dose of an extended-release formulation of naltrexone. 

This extended-release formulation means that the medication is released slowly into the bloodstream over the course of a month.[5] A sustained release of the medication helps to make sure that the patient maintains a level of naltrexone in the blood that is significant enough to continually block the opioid receptors all month.

Lesser Cravings

Another effect that occurs when Vivitrol blocks the opioid receptors in the brain is a reaction in cravings for opioids and alcohol.[6] Often, the psychological dependence on the substance is harder to overcome in the long term than the initial withdrawal symptoms. This makes Vivitrol extremely valuable, as decreasing cravings can lead to a significantly decreased risk of relapse to the substance of choice. 

Overdose Risk Reduction

Vivitrol can cut down on the risk of overdose that comes with relapse, especially if the drug of choice is opioids. Because naltrexone works to block the effects of opioid overdose, it is very difficult for someone to take so much that they override the medication and get high or experience respiratory depression, which is the most common cause of overdose death. As long as naltrexone is at therapeutic levels in the body, overdose is not likely.[7]

In fact, most people who attempt to take opioids while on Vivitrol will be thrown into precipitated withdrawal within minutes. This is why it is advised that people fully understand the nature of Vivitrol before they receive it.[8]

Not a Silver Bullet Approach

Vivitrol is not designed to be a singular approach to addressing something as serious as an opioid dependence or alcohol addiction. It is meant to be a part of a comprehensive program that includes therapy, peer groups, holistic treatments, and experiential therapies that help the person to address the underlying issues driving addiction and make lifestyle changes that will sustain them for the long term in recovery.[3]

How Long Does It Take for Vivitrol to Kick in? 

Generally, Vivitrol takes effect and will serve the purpose of blocking the opioid receptors shortly after the shot is administered. For most people, it begins working within a few hours to one day after getting the shot, as naltrexone levels in the blood slowly build up over time.[2] Once sufficiently therapeutic levels are reached, it will be able to block opioids and reduce cravings for alcohol. 

However, everyone is different. The exact time it takes to be effective will vary based on a number of factors, including which opioids or other substances are in the person’s system and how they interact (or not) with naltrexone. 

The person’s individual rate of metabolism is also a factor. Those who have a slower metabolism or are taking medications that alter how naltrexone is metabolized will find that it takes longer to work. Those who have a fast metabolism will find that it’s effective much more quickly.[9] For many, it may not reach full effect until a few days have passed. 

Because everyone is different, it is not recommended to use Vivitrol until you have been free of opioid use for a week to 10 days.

How Is Vivitrol Different Than Other Forms of MAT?

It’s important to note that Vivitrol does not usually trigger withdrawal symptoms or reverse the effects of opioids that are already in the system when Vivitrol is introduced. That is, it is not designed to be a replacement for naloxone, which does override opioids currently in the system. Vivitrol functions differently compared to medications that contain naloxone, such as Suboxone.[10]

Instead, Vivitrol is designed to be a preventative measure against future use of substances. 

How Long Does Vivitrol Stay in Your System?

Vivitrol is a monthly shot, so it is designed to be at peak effect for up to 30. However, all effects of the drug do not disappear completely on day 31.

Vivitrol’s Half-Life

Vivitrol has a relatively long half-life, which is the amount of time it takes for about half of the dose of the drug to be completely eliminated from the body. Depending on metabolism, liver function, and other factors, it can take anywhere from five to 10 days for half of a Vivitrol dose to be processed out of the system.[11] 

Since it takes about four to five half-lives for a drug to be considered out of the body and no longer effective, Vivitrol may continue to have effects for anywhere from 25 to 50 days after the last day of peak effect.[12]

Detectability on Drug Tests

When it comes to detecting Vivitrol in the body, the time frame at which detectable levels will be in one’s system will depend on the style of test (urine, blood, or hair test) as well as the metabolism of the individual. 

A urine test looking for opioids would not generally have a positive result with Vivitrol in one’s system even though the drug binds to opioid receptors.[13] However, there have been reports of false positives while a person is on naltrexone.[15] But in most cases, a specialized test would need to be administered to detect Vivitrol. 

Get Personalized Guidance

If you would like to learn more about Vivitrol and its applications to determine if it’s a good choice for your addiction treatment or the recovery of a loved one, reach out today. After a complete assessment, your doctor will assess whether Vivitrol or another form of MAT is right for your situation. When used as part of a comprehensive treatment approach, it can help to sustain your long-term recovery.

Updated April 11, 2024
  1. Naltrexone. Substance Abuse and Mental Health Services. Published 2023. Accessed March 26, 2024.
  2. Chapter 5 – Extended-release injectable naltrexone. Substance Abuse and Mental Health Services Administration. Published 2009. Accessed March 26, 2024.
  3. Medication assisted treatment. Pennsylvania Department of Corrections. Published 2019. Accessed March 26, 2024.
  4. AATOD guidelines for using naltrexone (Vivitrol) in OTPs. Commonwealth of Massachusetts. Accessed March 26, 2024.
  5. An introduction to extended-release injectable naltrexone for the treatment of people with opioid dependence. Substance Abuse and Mental Health Services.  Published 2012. Accessed March 26, 2024.
  6. Kim Y, Hack L, Ahn ES, Kim J. Practical outpatient pharmacotherapy for alcohol use disorder. Drugs in Context. 2018;7:1-14.
  7. Binswanger IA, Glanz JM. Potential risk window for opioid overdose related to treatment with extended-release injectable naltrexone. Drug Safety. 2018;41(10):979-980.
  8. Vivitrol treatment consent and agreement I. Vivitrol Medication Guide. Indian Health Services. Accessed March 26, 2024.
  9. Zhang Z, Tang W. Drug metabolism in drug discovery and development. Acta Pharmaceutica Sinica B. 2018;8(5):721-732.
  10. Lee JD, Nunes EV, Novo P, et al. Comparative effectiveness of extended release naltrexone versus buprenorphine naloxone for opioid relapse prevention (X:BOT): a multicentre, open label, randomised controlled trial. The Lancet. 2018;391(10118):309-318.
  11. Singh D, Saadabadi A. Naltrexone. StatPearls. Published 2020. Accessed March 26, 2024.
  12. Ito S. Pharmacokinetics 101. Paediatrics & Child Health. 2011;16(9):535-536.
  13. Storrow AB, Wians FH, Mikkelsen SL, Norton J. Does naloxone cause a positive urine opiate screen? Annals of Emergency Medicine. 1994;24(6):1151-1153.
  14. Vivitrol (naltrexone for extended-release injectable suspension). Alkermes. Published 2009. Accessed March 26, 2024.
  15. Plant E, Yang L, Hering R, Nerenberg L. False positive urine drug screens in patients receiving oral naltrexone. The Canadian Journal of Addiction. 2019;10(2):25-26.
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