The most important thing to avoid when taking naltrexone is opioids of any kind. Naltrexone blocks opioids, so taking them while on it will not work, and starting naltrexone while opioids are still in your body can trigger sudden, severe withdrawal. You should be free of all opioids for 7 to 10 days before your first dose. Beyond opioids, there are a few other things worth knowing.
What is the most important thing to avoid?
Opioids. This is the one rule that matters most. Naltrexone works by blocking opioid receptors, the same receptors that opioid painkillers and heroin act on. While you are on naltrexone, those drugs will have little or no effect, so they will not relieve pain or produce a high. More importantly, if you start naltrexone while opioids are still in your system, the medication can knock them off the receptors all at once and cause a sudden, intense withdrawal called precipitated withdrawal.
This includes every kind of opioid: prescription painkillers like oxycodone, hydrocodone, morphine, and codeine, as well as methadone, buprenorphine, tramadol, and heroin. Always tell your provider about any opioid you have taken recently.
Be opioid-free before you start
Before your first dose, you need to be off all opioids. This waiting period lets your body clear the opioids so naltrexone does not trigger withdrawal. Your provider may ask questions or use a simple test to confirm you are ready. Never shorten this window on your own.
Short-acting opioids
Oxycodone, hydrocodone, or heroin. Usually 7 to 10 days opioid-free before your first dose.
7 to 10 daysLong-acting opioids
Methadone or buprenorphine. Usually 10 to 14 days before you start.
10 to 14 daysOpioid medicines that hide in plain sight
Some everyday medicines contain opioids without making it obvious. Prescription cough syrups often contain codeine or hydrocodone. Some anti-diarrhea medicines contain diphenoxylate or loperamide. Certain cold and flu combination products include an opioid cough suppressant. While you are on naltrexone, these will not work as intended, and they are worth avoiding unless your provider approves them. When in doubt, read the label or ask a pharmacist whether a product contains an opioid.
Surgery, dental work, and emergencies
If you need surgery, a dental procedure, or emergency care, tell every provider that you take naltrexone. Because it blocks opioid painkillers, standard opioid pain relief may not work while it is active. Your care team can plan ahead with non-opioid pain control or, for planned surgery, pause naltrexone at the right time. Carry a note or wear a medical ID if you can, so this information is available even in an emergency.
Can you drink alcohol on naltrexone?
Yes, in the sense that naltrexone will not make you sick if you drink. It is not disulfiram (Antabuse), which causes a violent reaction with alcohol. Naltrexone simply blunts the reward, so drinking feels less satisfying. That said, it is not a license to drink heavily. Naltrexone is meant to help you drink less over time, and heavy drinking is still hard on your body, especially your liver.
Naltrexone and your liver
At the standard 50 mg dose, naltrexone is gentle on the liver for most people. It should be avoided if you have acute hepatitis or liver failure, and used with care if you have serious liver disease. Because heavy alcohol use is itself tough on the liver, your provider may check your liver with a simple blood test before and during treatment. This is routine and nothing to worry about for most people.
What to avoid at a glance
| Avoid | Why |
|---|---|
| All opioid drugs | Blocked by naltrexone, and can trigger sudden withdrawal |
| Opioid cough, cold, and diarrhea medicines | Contain hidden opioids that will not work and are best avoided |
| Starting too soon | Be opioid-free 7 to 10 days first to prevent withdrawal |
| Overriding the block with more opioids | High overdose risk |
| Heavy drinking | Not dangerous with naltrexone, but still harmful to your health |
For the full picture, see our naltrexone for alcohol guide, naltrexone drug interactions, and naltrexone side effects.
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No spam. We will only email you about naltrexone for alcohol at Recovery Delivered.Frequently asked questions
What should you avoid when taking naltrexone?
Can you drink alcohol while taking naltrexone?
What happens if you take an opioid on naltrexone?
How long before naltrexone should you stop opioids?
Daniel R. Karlin, MD, MA
Board-certified psychiatrist and addiction medicine specialist. Author of 21+ peer-reviewed publications (1,355 citations) including recent work in JAMA (2025) and the British Journal of Psychiatry (2023).
- Sources. U.S. Food and Drug Administration. Prescribing information for naltrexone (ReVia) and naltrexone extended-release injectable (Vivitrol), including opioid-free interval and precipitated withdrawal warnings.
- Singh D, Saadabadi A. Naltrexone. StatPearls. National Library of Medicine.
- Substance Abuse and Mental Health Services Administration (SAMHSA). Naltrexone guidance for treatment of alcohol and opioid use disorder.
This page is for education only and is not medical advice. Naltrexone is a prescription medication. Talk with a licensed provider about whether it is right for you.
