Key takeaways
- Naltrexone is a prescription medication used to manage both alcohol and opioid use disorders in adults.
- The typical oral dosage of naltrexone for alcohol use disorder is 50 milligrams (mg) daily. For opioid use disorder, you usually start with 25 mg for the first dose, then take 50 mg daily.
- While naltrexone isn’t typically taken for weight loss, a combination drug called Contrave, which includes naltrexone and bupropion, is approved for this purpose.
Naltrexone oral tablet is a prescription drug used to treat alcohol use disorder and opioid use disorder in adults. It’s usually taken once per day.
Naltrexone belongs to a group of drugs called opioid antagonists. This article describes the dosage of naltrexone oral tablet, as well as its strength and how to take it. To learn more about this drug, including its uses and side effects, see this naltrexone oral tablet overview article.
Naltrexone oral tablet comes in a strength of 50 milligrams (mg).
The following table shows the commonly prescribed dosages of the drug. But be sure to take the dosage your doctor prescribes for you. They’ll determine the best dosage of naltrexone oral tablet for your needs.
| Condition | Starting dose | Ongoing (maintenance) dose |
|---|---|---|
| Alcohol use disorder | 50 mg once per day | 50 mg once per day |
| Opioid use disorder | 25 mg once per day | 50 mg once per day |
Is naltrexone used long term?
Yes, naltrexone oral tablet is usually prescribed as a long-term treatment. If you and your doctor determine that it’s safe and effective for you, you’ll likely take it long term.
Dosage adjustments
Your doctor may lower your naltrexone dosage if your liver or kidneys aren’t functioning well. They may also lower your dosage if you take certain other medications.
During your naltrexone treatment, talk with your doctor before you start or stop taking any other medications.
If you’re prescribed Naltrexone tablet, you’ll typically swallow it whole. If you have trouble swallowing tablets, see these tips for how to swallow a pill.
Naltrexone oral tablets are scored — they have a grooved line to help you break them in half if needed. But check with your doctor before crushing or chewing these tablets.
You can take naltrexone oral tablet with or without food.
If you miss a dose of naltrexone oral tablet, take it as soon as you remember. But if it’s almost time for your next dose, skip the missed dose and take your next dose at its usual time. If you’re not sure whether you should take a missed dose, talk with your doctor or pharmacist.
If you need help remembering to take your dose of naltrexone on time, try using a medication reminder. This can include setting an alarm or using a reminder app on your phone.
Do not take more naltrexone oral tablet than your doctor prescribes, as this can lead to harmful effects.
What to do in case you take too much naltrexone
Call your doctor right away if you think you’ve taken too much X drug. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.
Taking naltrexone oral tablet does not lead to dependence. With dependence, your body needs the drug to feel like it usually does. If you stop taking a drug you’re dependent on, you may have withdrawal symptoms. You won’t have withdrawal symptoms if you suddenly stop taking naltrexone oral tablet.
If you have questions about naltrexone and the risk of dependence or withdrawal symptoms, talk with your doctor.
Below are answers to some commonly asked questions about naltrexone oral tablet dosage.
Can naltrexone be used for weight loss? If so, what’s the dosage?
No, naltrexone is not prescribed for weight loss.
Because naltrexone isn’t used for weight loss, the drug manufacturer doesn’t provide recommended dosages for this use.
However, Contrave (naltrexone/bupropion) is a combination drug that’s approved for weight loss. It contains naltrexone with another active ingredient called bupropion. (An active ingredient is what makes a medication work.) To learn more about this and other treatment options for weight loss, talk with your doctor.
How long does it take for naltrexone to start working?
Naltrexone oral tablet starts to work after your first dose. Because of how the drug works, you likely won’t feel the drug working in your body. But your doctor will monitor you during treatment to check whether the drug is working to treat your condition.
If you have other questions about what to expect from your naltrexone treatment, talk with your doctor.
Disclaimer: Healthline 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.