Naltrexone (Revia/Vivitrol)

What naltrexone is

Naltrexone is a medication sold under the brand name Revia as a daily tablet and Vivitrol as a monthly injection given in a clinic. It works by blocking opioid receptors, the docking points that opioids act on and that also play a part in the reward tied to alcohol. By blocking them, it lowers cravings and takes away the high from opioids. It is not a controlled medicine and is not habit-forming.

What it treats

Your clinician might suggest naltrexone for one of these, among other possible off-label uses:

• Alcohol use disorder, to reduce cravings and support cutting back or staying off alcohol
• Opioid use disorder, to help prevent return to use after someone has stopped opioids

It works best as one part of a broader plan rather than on its own. Whether it is a good fit depends on several factors, including your history and your goals. As with everything in psychiatry, that is decided case by case.

How it works

Honestly, no one knows with complete certainty how naltrexone produces all of its benefit. What research supports is that it blocks opioid receptors, which both removes the high from opioids and seems to quiet the craving and reward that can drive drinking. The biology is only part of the picture: how much a medication helps, and how it feels, is individual. Two people on the same medication can have very different experiences.

How to take it

There is no single right way to take naltrexone; it depends on you and your clinician, including whether the daily tablet or the monthly injection fits your situation better. The plan you and your clinician make together is the one to follow. A few points matter here:

• Be opioid-free before starting. Because naltrexone blocks opioids, starting it too soon can cause sudden, severe withdrawal. Your clinician will confirm enough time has passed.
• Know that your opioid tolerance drops while you are on it. If someone returns to opioids during treatment or after stopping, a previously usual amount can become dangerous or fatal. This is important to understand honestly.
• Carry a note or card that says you take naltrexone, so that in an emergency a care team knows ordinary opioid pain relief may not work normally for you.
• If you miss a tablet, ask your clinician what to do rather than doubling up.

What to expect

This varies from person to person. Naltrexone is usually one part of a plan that also includes support and other steps, and it tends to help most when it is paired with those. Any side effects, if they happen, often show up early and ease. If it does not turn out to be the right fit, that is useful information, not a dead end, and there are other options. As always, this is case by case.

Low-dose naltrexone

You may have heard of low-dose naltrexone, sometimes shortened to LDN. This means naltrexone used at a much smaller dose than the one used for alcohol or opioid use, and it is being used or studied off-label for a range of other conditions, such as some chronic pain conditions like fibromyalgia. It is worth being plain about where this stands: outside its approved uses, the evidence for low-dose naltrexone is still limited and early, it is not a proven treatment for most of these conditions, and it is not right for everyone. Some people and clinicians find it worth trying in specific situations, as part of a broader plan and with realistic expectations. If you are curious about it, it is a reasonable conversation to have with your clinician, who can weigh whether it makes sense for you. As with everything in psychiatry, that is decided case by case.

Side effects

Not everyone gets side effects, and many that do happen ease over the first weeks. The lists below are possibilities, not certainties.

Possible more common side effects:

• Nausea, especially early on
• Headache
• Dizziness
• Trouble sleeping or feeling anxious
• Muscle or joint aches
• Tiredness
• With the injection, soreness or a lump at the injection site

If any of these stick around or bother you, they are worth raising. Send a non-urgent message through the patient portal or bring it up at your next visit; often a small change helps.

Less common, but concerning side effects that could require emergency care:

• Signs of a liver problem: pain in the upper-right belly that does not go away, yellowing of the skin or eyes, dark urine, or unusual tiredness
• Signs of an allergic reaction: rash, hives, or swelling of the face, lips, tongue, or throat, or trouble breathing
• A severe reaction at the injection site, such as intense pain, blistering, or an open wound
• Any new or worsening thoughts of harming yourself

For any of these, use the help options at the top of this page: call 911 or go to the nearest emergency department for a medical emergency or severe reaction, or call or text 988 for a mental health crisis.

When to reach out, and where

For routine questions, side effects that can wait, or how things are going, send your clinician a message through the patient portal. These are part of your ongoing care and are answered in the normal course of a few business days, so they are best for things that are not urgent.

If something feels urgent, you do not need to wait for a reply. The help options at the top of this page are the fastest way to get care: 911 or the nearest emergency department for a medical emergency or severe reaction, or 988 any time for a mental health crisis or thoughts of self-harm.

Questions to ask your clinician

• What are you hoping naltrexone will help with in my case?
• Would the daily tablet or the monthly injection fit my situation better?
• How long do I need to be off opioids before starting?
• How does this fit with the other parts of my plan?
• What is the plan if this one turns out not to be the right fit?