Medically reviewed badge

Naltrexone Use in Addiction Treatment

Naltrexone is used for the treatment of opioid and alcohol addiction, as it blocks the high and diminishes some of the rewards associated with drinking.

Questions about treatment?
  • Access to licensed treatment centers
  • Information on treatment plans
  • Financial assistance options
We're available 24/7
Call American Addictions centers help information

Naltrexone does not treat withdrawal. Unlike some other medications that are used to manage symptoms during detox, naltrexone should not be taken by someone still acutely withdrawing from opioids and is best utilized in someone who has already attempted to abstain from alcohol for several days or has already gone through a medically assisted alcohol detox.

Naltrexone is used for the post-detox treatment of opioid and alcohol addiction, as it blocks the subjective high from opioids and diminishes some of the rewards associated with drinking. It is available in tablet form or as an extended-release injection (Vivitrol).1,2 When taken too soon in someone with opioid dependence, naltrexone can, in fact, trigger or worsen withdrawal symptoms.2 Studies have documented precipitated withdrawal cases among people opioid-dependent individuals who start naltrexone without fully detoxing off of opioids first.1

It is recommended that people who are dependent on opioids, such as heroin or morphine stop their use of opioids at least 7 to 10 days before you begin a naltrexone medication. Those making the switch from a methadone maintenance regimen or other medically-assisted treatment scenario involving methadone to naltrexone must be completely detoxed from opioids first.3

Like all addiction medication, naltrexone should be used as a component of more comprehensive recovery efforts that include behavioral therapy and psychosocial support to improve treatment outcomes.4 

Does your insurance cover rehab for opioids?

We can help – check your coverage instantly or text us your questions to find out more.

How Does It Naltrexone Work?

Naltrexone is a medication approved by the Food and Drug Administration (FDA) to treat opioid use disorders and alcohol use disorders.

It is one of several types of medications used in the treatment of opioid addiction. The other two are methadone, a full opioid receptor agonist, and buprenorphine, a partial agonist. Both bind to and activate the brain’s opioid receptors to different degrees to alleviate some of the unpleasant opioid withdrawal symptoms and relieve cravings.

Naltrexone differs from these two in that it is an opioid antagonist, which means that it inhibits the activation of opioid receptors in the brain.3 If you use opioids, it will block the euphoria and sedation you would normally feel if you were not taking naltrexone.

This opioid antagonizing effect of naltrexone also helps to limit some of the rewarding effects associated with alcohol and, in doing so, decreases continued drinking behavior and reduces the likelihood of relapse in those dedicated to recovering from compulsive alcohol use. There is some evidence that naltrexone also helps to reduce alcohol cravings.5 A consistent naltrexone regimen may diminish some of the motivation to continue using either opioids or alcohol.3

Again, naltrexone is not used as an opioid or alcohol detox medication. As mentioned, naltrexone can initiate or worsen an already severe opioid withdrawal experience when taken prematurely. Instead, naltrexone is used to help people stay clean and sober once the withdrawal phase of treatment has ended.6 

How Is Naltrexone Administered?

Naltrexone is available in a pill form, or as a long-acting injectable version.6

The pill form is taken orally every day. Because the pill needs to be taken regularly to be effective, compliance to treatment can be an issue; in fact, doctors note that failure to take the medication is common among their patients.

The once-a-month naltrexone injection, Vivitrol, makes it much easier to adhere to your medication regimen and is a great option for people who forget to, or simply don’t want to, take a pill several times per week.7

Does Naltrexone Reduce Cravings?

You should not expect naltrexone to completely remove all cravings or urges you have to use alcohol or opioids. However, you may still want to use them for any number of reasons. There is evidence that, because naltrexone reduces the reward and makes abusing opioids or alcohol a less pleasant experience, it may eventually decrease a person’s cravings and desire to use these drugs.3

Again, naltrexone is not like methadone in that it doesn’t produce opioid effects in your brain to help lower your cravings; rather, it prevents alcohol or opioids from activating your opioid receptors in order to prevent feeling the pleasurable effects of the drugs. The idea behind naltrexone is that without the euphoric high you’re used to, the drugs won’t hold the same appeal. Through its opioid antagonist action, naltrexone:8

  1. Helps individuals stay away from using alcohol or opioids.
  2. Reduces a person’s desire to drink alcohol.
  3. Helps prevent relapse.

Relapse risks may be extremely high among people who have recently completed a short course of residential treatment, but medications like injectable naltrexone can help protect against relapsing back to opioid abuse.9

In a study of people incarcerated within the U.S. criminal system, researchers found that those who were given Vivitrol reported lower rates of opioid relapse than those who didn’t receive the medication.10

What Should I Know Before Taking Naltrexone?

You need to wait until the appropriate time to begin taking naltrexone. If you are withdrawing in a medical detox, your treatment team will know when to begin your naltrexone treatment. Otherwise, your doctor can advise you when to begin taking the drug and will monitor your treatment. It’s important not to take any more or less naltrexone than your physician has prescribed.2

Other things to consider when taking naltrexone include the following:11

  • Missing doses of naltrexone can increase your risk of relapse. If you miss a dose do not double up on your next dose – just take it as soon as you remember.
  • You should not stop taking naltrexone until your doctor has communicated to you that it is time to cease your medication regime.
  • While taking the medication, avoid alcohol and opioid medications.
  • If you suffer from depression or suicidal thoughts, share that with your doctor. If you feel like you may harm yourself or others, call 9-1-1 or visit your closest emergency room.

During a period of abstinence from opioids, your tolerance may decrease, and you’ll be more sensitive to opioids if you take them again. This means that even lower doses than you took before starting treatment could cause you to fatally overdose.1 Because of this, it is extremely important that you are connected to a comprehensive treatment program that includes therapy and professional support so you can seek help if you feel yourself slipping into a potential relapse.3 

Who Should Use Naltrexone?

If you are using naltrexone, you should not continue drinking or using drugs.3 Naltrexone alone is not enough to treat addiction. You should use this medication if you are committed to ending your substance use and can engage in a treatment regimen that incorporates behavioral therapeutic approaches in addition to medication.

Your treatment team can help you approach your addiction from numerous angles and can facilitate participation in activities such as group or individual counseling, life skills training, and more so that you are as prepared as possible to live in recovery and face the challenges that come with staying abstinent.6 Medication is only a small part of a more comprehensive recovery plan.

Who Should Avoid Naltrexone?

Naltrexone is widely used in alcohol and opioid addiction treatment; however, it may not be safe for those with:8

  • Acute hepatitis.
  • Liver failure.
  • Chronic pain (and who are using painkillers).

Naltrexone is not appropriate for everyone. You should avoid using this drug and ask your doctor for any alternatives if:2

  • You are currently in withdrawal.
  • You are still using heroin or other opioid drugs or still drinking alcohol.

Naltrexone might not be safe for pregnant or breastfeeding women. Learn more below.

What Are the Side Effects of Naltrexone?

Common side effects of naltrexone include:3

  • Diarrhea.
  • Headache.
  • Sleep problems.
  • Stomach upset.
  • Joint pain.
  • Nervousness.

If you are prescribed naltrexone as part of your treatment and you are experiencing side effects, speak to your doctor about adjusting your dose or changing your medication.

In large doses, naltrexone use may cause liver damage. Symptoms include:2

  • Loss of appetite.
  • Dark urine.
  • Feeling very tired.
  • Unusual bleeding.
  • Bruising.
  • Stomach pain for more than a few days.
  • Yellowing of the skin or eyes.

If you notice these symptoms, seek medical attention right away.

Can Naltrexone Be Used During Pregnancy?

Researchers are still investigating whether naltrexone is safe to use during pregnancy. However, recent studies have found that naltrexone may be an effective treatment approach in managing opioid dependence in pregnant women. If a woman is pregnant, she will likely require a specialized detox, and naltrexone may be a promising addition to an opioid-dependent woman’s treatment options.12

One study found that when opioid-dependent pregnant women were treated with naltrexone, their babies had shorter hospital stays and lower rates of neonatal abstinence syndrome compared to newborns whose mothers were given buprenorphine or methadone. Although this non-controlled study had certain limitations, the findings point to the need for further research in the field.12

A handful of studies conducted on animals who were given very high doses of naltrexone showed that when the animal fetus is exposed to the medication, it can cause physical and behavioral defects including miscarriage, high birth weight, and longer body length. Because these studies were conducted with very high doses of naltrexone (much higher than the human dose), researchers were unable to generalize these effects to a human fetus.12

When considering the risks of opioid medications on mother and child, it’s important to also weigh the risks of continuing to abuse opioids such as heroin. Continued opioid misuse during pregnancy can lead to a number of consequences for a baby, including:12

  • Stillbirth.
  • Miscarriage.
  • Neonatal abstinence syndrome.
  • Preterm labor.
  • Fetal convulsions.

It is important that if you are pregnant and using opioids that you get the help you need. This may not include naltrexone, since it’s still being studied; you may be offered methadone or buprenorphine and should also receive therapy. There are professional treatment programs available to help you safely stop using opioids and prevent further harm to you and your baby.12

Naltrexone Information at a Glance2,13,14
Medication Name, Costs Class of Medicine
  • Generic Name: Naltrexone
  • Brand Name: Vivitrol
  • Mechanism of Action: Opioid antagonist
  • Used to Treat Addiction? Yes
  • Function or Use at Low Dose: Used to lessen cravings for alcohol and decrease the euphoria associated with alcohol and opioids.
Form, Intake and Dosage Interactions and Complications
  • Drug Forms: Oral tablet, extended-release suspension for intramuscular (IM) injection
  • Administration Routes: Oral or (IM)
  • Dosing: 25 mg to 50 mg PO, daily or 380 mg IM, q4 weeks depending on the form.
  • Contraindications: Acute hepatitis or liver failure, concomitant opioid use
Effects and Adverse Reactions Substance Abuse
  • Short-Term: Headache, dizziness, nervousness, fatigue, restlessness, insomnia, anxiety, nausea, irritability, rash, joint pain
  • Long-Term: Liver damage
  • Risk of Substance Abuse: None