What To Avoid When Taking Low-Dose Naltrexone
- October 4, 2023
- , Medications, Naltrexone
Updated September 2026.
The thing to avoid first when taking low-dose naltrexone (LDN) is opioids of any kind. Naltrexone is an opioid antagonist: it blocks opioid receptors. Opioid painkillers will not work as intended, and starting naltrexone while opioids are still in your body can trigger sudden, severe withdrawal. Some cough, cold, and anti-diarrhea medicines hide opioids. Naltrexone is not disulfiram (Antabuse), so it does not make you sick if you drink, and there is no required wait between a dose and alcohol for that reason. Heavy drinking is still harmful. Take LDN at the time your prescriber set, often once a day. Call a clinician if you have warning signs such as yellowing skin or eyes, trouble breathing, or sudden withdrawal. This page is education, not personal medical advice.
| Avoid | Why |
|---|---|
| All opioid drugs | Naltrexone blocks them. Starting too soon can trigger precipitated withdrawal. |
| Hidden opioids in cough, cold, and diarrhea medicines | Codeine, hydrocodone, diphenoxylate, and loperamide are still opioids. |
| Starting too soon after opioids | Standard labels typically need 7 to 10 days opioid-free (often 10 to 14 after methadone or buprenorphine). Your prescriber sets the window. |
| Trying to override the block | Life-threatening overdose risk. Tolerance is lower after you stop. |
| Heavy drinking | No Antabuse-style reaction and no required wait, but still hard on the liver. |
| Unreviewed interactions | Tell your provider about thioridazine, disulfiram, yohimbine, and every opioid-containing OTC. |
What to avoid on LDN
- All opioid drugs. Prescription painkillers such as oxycodone, hydrocodone, morphine, codeine, tramadol, and fentanyl, plus methadone, buprenorphine, and heroin. Naltrexone blocks them. Starting LDN too soon can cause precipitated withdrawal.
- Hidden opioids. Some prescription cough syrups contain codeine or hydrocodone. Some anti-diarrhea products contain diphenoxylate or loperamide. A few cold and flu combination products include an opioid cough suppressant. Ask a pharmacist if you are unsure.
- Starting too soon after opioids. FDA-approved naltrexone labels typically require people to be opioid-free for 7 to 10 days before the first dose (often 10 to 14 days after methadone or buprenorphine). LDN is a much smaller dose, but it is still naltrexone. Your prescriber will tell you what applies to your plan. Do not shorten that window on your own.
- Trying to override the block. Never take large amounts of opioids to push past naltrexone. That can cause a life-threatening overdose. After you stop naltrexone, your tolerance to opioids is lower than before, so a previous opioid amount can also cause an overdose.
- Heavy drinking. Naltrexone does not cause an Antabuse reaction. Heavy drinking is still hard on the liver and on your health. Talk with your provider about alcohol while you are on LDN.
For the standard 50 mg naltrexone used for alcohol use disorder, see what to avoid on naltrexone and our naltrexone guide.
What low-dose naltrexone is, and what it is not
Naltrexone is a prescription opioid antagonist. It sits on opioid receptors and blocks them. It is not an opioid agonist. An antagonist blocks. An agonist activates.
On this site, low-dose naltrexone means a much smaller dose than the 50 mg tablet used for alcohol use disorder, commonly discussed as about 1.5 mg to 4.5 mg. Naltrexone is FDA-approved for alcohol use disorder and opioid use disorder at those standard doses. LDN for chronic pain or other conditions is a different, off-label use. Your prescriber decides whether it is appropriate for you.
LDN is not a substitute for opioid withdrawal care, and it is not the 50 mg naltrexone dose used to treat alcohol use disorder. If your goal is drinking less, start with the naltrexone for alcohol guide.
Opioids: the rule that matters most
This is the one rule that matters most. While naltrexone is occupying opioid receptors, opioid medicines will have little or no effect, so they will not relieve pain the way they usually do. If opioids are still in your body when naltrexone is started, the medication can knock them off the receptors all at once and cause precipitated withdrawal.
Always tell your provider about any opioid you have taken recently, including medicines that do not look like painkillers. If you need surgery, dental work, or emergency care, tell every clinician you take naltrexone so they can plan non-opioid pain control, or pause the medicine at the right time. Carry a note or a medical ID if you can.
Alcohol timing on LDN
Naltrexone is not disulfiram (Antabuse). It will not make you flush, vomit, or get sick because you drank. There is no required wait between a dose of naltrexone and alcohol the way there is with disulfiram.
That is not a license to drink heavily. Naltrexone is processed by the liver. Heavy drinking is hard on the liver regardless of the medication. If you are using LDN for another condition, alcohol can also work against the reason you are taking it. Tell your provider how much you drink and follow their advice.
If you are taking naltrexone specifically to drink less, that is usually the 50 mg daily tablet or the monthly injection, not LDN. See what naltrexone is and naltrexone dosing.
When to take LDN
Take the exact dose your prescriber wrote, at the time they set. Do not raise, lower, or skip doses on your own.
Many people take LDN once a day. Some take it at night. Some take it in the morning if night dosing disrupts sleep or causes vivid dreams. The same practical rule we use for standard-dose naltrexone applies here: pick a time you can keep consistent, with or without food, and ask your provider to switch morning and night if sleep or drowsiness is a problem.
This is general education. It is not a personal dosing plan. Only the clinician who knows your history can set your dose and timing.
Other interactions to tell your provider about
Give your provider and pharmacist a full list of everything you take, including over-the-counter products and supplements. The naltrexone labels used on this site also note:
- Opioid-containing cough, cold, and diarrhea medicines — avoid unless your provider clears them. See naltrexone interactions.
- Thioridazine — can cause more drowsiness with naltrexone.
- Disulfiram (Antabuse) — both are processed by the liver; they are combined only with careful monitoring.
- Yohimbine — the Vivitrol injection label notes a possible interaction.
Non-opioid pain relievers such as acetaminophen or ibuprofen are generally fine. They are not a labeled naltrexone interaction. Still, check with your prescriber if you have stomach, kidney, or bleeding risks of your own.
Naltrexone is not known to have a major interaction with common antidepressants, and the two are often used together. Share the full list anyway.
When to call or seek care
Most people who take naltrexone have mild effects, if any, such as nausea, headache, fatigue, or sleep changes. Those often ease. Call your provider or seek urgent care if you notice:
- Stomach pain that does not go away, dark urine, or yellowing of the skin or eyes (possible liver signs).
- Rash, swelling, or trouble breathing (possible allergy).
- Sudden, intense withdrawal after a dose, especially if opioids were still in your system.
- New or worsening low mood.
If this is an emergency, call 911. For Recovery Delivered questions about care we already provide, text or call Contact support. After you stop naltrexone, opioid tolerance is lower, which raises overdose risk if you return to opioids. Talk with your provider before you stop.
More detail lives on naltrexone side effects and whether naltrexone side effects go away.
Naltrexone at Recovery Delivered
If you are looking for naltrexone for alcohol use disorder, start with our naltrexone service and education page. Naltrexone treatment is coming to Recovery Delivered; that page is the place to read how care will work. LDN for pain or other off-label uses is a separate clinical decision and is not something this page can promise.
Frequently asked questions
What should you avoid when taking low-dose naltrexone?
Avoid all opioids, including prescription painkillers, heroin, methadone, buprenorphine, tramadol, and opioid-containing cough, cold, and diarrhea medicines. Be opioid-free before you start, on the timeline your prescriber sets, and never take extra opioids to try to override the block.
Can you drink alcohol while taking low-dose naltrexone?
Naltrexone does not cause a sick reaction with alcohol the way disulfiram (Antabuse) does, so there is no required wait between a dose and a drink for that reason. Heavy drinking is still harmful, especially to the liver. Talk with your provider about alcohol while you are on LDN.
Can you take opioid painkillers with LDN?
Opioid painkillers will not work as intended while naltrexone is blocking the receptors. Non-opioid options such as acetaminophen or ibuprofen are generally fine. For surgery or serious pain, tell every clinician you take naltrexone.
When should you take low-dose naltrexone, morning or night?
Take it the way your prescriber told you. Many people take LDN once a day. Some take it at night; some take it in the morning if night dosing disrupts sleep. Pick a consistent time. Do not change your dose on your own.
When should you call a doctor while taking LDN?
Call your provider or seek care for ongoing stomach pain, dark urine, or yellow skin or eyes; rash, swelling, or trouble breathing; sudden severe withdrawal after a dose; or new or worsening low mood. After you stop naltrexone, opioid tolerance is lower, which raises overdose risk if you return to opioids.
Sources. U.S. Food and Drug Administration prescribing information for naltrexone (ReVia) and naltrexone extended-release injectable (Vivitrol), including the 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 alcohol and opioid use disorder. See also Recovery Delivered’s naltrexone guide.
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. Never start, stop, or change a dose without that conversation.
Author
Author: marcus Marcus is a Co-Founder of Recovery Delivered. He has been working in addiction for over 12 years and has vast industry knowledge. His main priority is helping as many people as possible get off opioids and, most importantly, stay off opioids. "I want to give women their husbands back, men their wives back, mothers and fathers their children back, and children their parents back. That is my goal in life and why RecoveryDelivered.com is here" Email