What To Avoid When Taking Low-Dose Naltrexone

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. Heavy drinking is still harmful. Take LDN at the time your prescriber set. Call a clinician if you have warning signs such as yellowing skin or eyes, trouble breathing, or sudden withdrawal.

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 require people to be opioid-free for a period before the first dose. LDN is a much smaller dose, but it is still naltrexone. Do not assume an interval taken from a standard-dose label applies to every LDN plan. Your prescriber will tell you what applies to yours. Do not shorten that window on your own. DailyMed: Oral naltrexone prescribing information
• 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.

Low-dose naltrexone means a much smaller dose than the 50 mg tablet used for alcohol use disorder. 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. Evidence for LDN varies by condition and remains limited. 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. Do not stop effective opioid use disorder treatment simply to begin LDN. 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, including the formulation, the prescribed amount, and your last dose, 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.

That is not a license to drink heavily. Naltrexone does not make heavy drinking safe or treat alcohol withdrawal. Naltrexone is processed by the liver, and 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. SAMHSA: Naltrexone

If drinking is a concern, it needs its own assessment and treatment plan. NIAAA: Cutting down or quitting alcohol

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.

Pick a time you can keep consistent, and ask your provider before changing it if sleep or drowsiness is a problem. Ask whom to contact about side effects or a missed dose.

If a compounded product is prescribed, confirm the concentration, measuring method, pharmacy instructions, and storage. A number of milliliters is not meaningful without the concentration. Compounded medications are not FDA approved.

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. Mention liver disease, pregnancy plans, and alcohol use. Naltrexone labels also note:

• Opioid-containing cough, cold, and diarrhea medicines: avoid unless your provider clears them. See naltrexone interactions.
• Thioridazine: tell your provider if you take it.
• Disulfiram (Antabuse): both are processed by the liver, and they are combined only with careful monitoring.
• Yohimbine: the Vivitrol injection label notes a possible interaction.

Acetaminophen and ibuprofen are non-opioid pain relievers, and neither is listed as an interaction on the naltrexone label. Check with your prescriber or pharmacist before you use them, especially if you have liver, 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 get medical care right away 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, use our contact page. 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 guide. Recovery Delivered is not taking alcohol treatment bookings yet, and that guide explains how care will work. LDN for pain or other off-label uses is a separate clinical decision. Confirm with any practice whether it provides this off-label treatment, and how it would monitor your response, before you book.

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. 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. Acetaminophen and ibuprofen are not labeled naltrexone interactions, but check with your prescriber or pharmacist first. 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. Pick a consistent time, and ask your provider before switching between morning and night. 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: DailyMed: Oral naltrexone prescribing information. Singh D, Saadabadi A. Naltrexone. StatPearls. National Library of Medicine. Substance Abuse and Mental Health Services Administration naltrexone guidance for alcohol and opioid use disorder: SAMHSA: Naltrexone. See also Recovery Delivered's naltrexone guide.

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.

Looking for help with alcohol? Recovery Delivered is not taking alcohol treatment bookings yet. Get alerted when we launch this program