Past opioid use does not always block you from taking naltrexone. Yet, danger exists. If opioids remain in your body, naltrexone can trigger sudden withdrawal.
Share your opioid history with your prescriber. Before you start, list every medicine you take. Do not guess the safe time to begin.
This guide covers opioid safety for those on naltrexone for alcohol use disorder. Find more info in our guide to medications for alcohol use disorder. We are an editorial team that studies health topics. We are not a treatment provider and do not offer medical review.
Key Facts About Naltrexone and Opioid Use
Approved to treat alcohol use disorder, naltrexone is a specific medication.[1] The extended-release injectable form is also approved for opioid use disorder, but approval and use hinge on the specific formulation.[2] It functions by blocking opioid receptors.[2] If you have used opioids in the past, you may still use naltrexone for alcohol use disorder. However, current or recent opioid use changes the safety picture. If you are planning to start this medication, our guide to insurance coverage for naltrexone explains how to verify your benefits. For a closer look at how naltrexone works for alcohol cravings, see our guide to the Sinclair Method.
Overdose deaths are a serious issue in the U.S. In 2023, there were 105,007 drug overdose deaths.[3] These numbers show why safety matters. They do not measure the risk or effectiveness of naltrexone.
105,007
U.S. drug overdose deaths in 2023[3]
Understanding how naltrexone interacts with opioids is vital. Read our guide to medications for alcohol use disorder for more options.
The Link Between Naltrexone and Opioids
In the body, naltrexone blocks opioid receptors.[2] This action stops or lowers what opioid drugs do.[4]
Naltrexone can interact with opioid pain medicines.[4] If you use naltrexone, opioids may not act as planned. Talk to your doctor about pain care.
| Situation | What May Happen | Why It Matters | Safer Next Step |
|---|---|---|---|
| Naltrexone blocks opioid receptors | Naltrexone may block opioid medicines used for pain.[5] | Pain treatment may be affected.[5] | Tell your prescriber you take naltrexone if you need pain care. |
| You take naltrexone after recent opioid use | If you are physically dependent on opioids or start naltrexone too soon after opioid use, severe withdrawal can occur.[5] | The risk depends on physical dependence and timing.[5] | For severe withdrawal symptoms, call 911 or go to the nearest emergency room now. If no emergency symptoms are occurring, contact your prescriber promptly. |
Naltrexone Opioid Withdrawal: Why Time Is Key
Precipitated withdrawal is a serious safety concern. It is not the same as natural withdrawal that happens when a dependent person quits opioids.[5] Naltrexone can cause severe withdrawal if a person is dependent on opioids or takes naltrexone too soon after using them.[5] Our guide to opioid withdrawal vs overdose explains how to tell the two apart and what to do in each case.
This kind of withdrawal can be very bad.[5] Hospital care may be needed for some people, and a few may need intensive care.[5] Do not treat this at home. Do not pick a safe start day by yourself.
If you have severe withdrawal symptoms, call 911 or go to the nearest emergency room now. Reach out to your prescriber before starting naltrexone if you used opioids recently or are unsure of your last use.[5] Your prescriber can check recent opioid use and possible physical dependence before treatment begins.[5] Our guide to detox to maintenance therapy transition explains the next steps in your opioid care plan.
Naltrexone and Opioid Use: Does Your History Matter?
Past opioid use is not the same as current need. Yet that history does not make starting naltrexone safe. The FDA label warns that naltrexone causes withdrawal symptoms in people physically dependent on opioids.[5] Doctors must check for recent use and opioid dependence before you begin.[5]
Your clinician will ask detailed questions about your opioid use. They want to know what you took and when. This includes prescriptions, store-bought items, and other sources. If the doctor does not know about your use, withdrawal can occur.[5] No single day count fits everyone. Safe timing relies on your specific opioid and situation. Starting too soon can cause withdrawal severe enough to require hospital care.[5]
Prepare for your visit using this checklist. You can also find more tips in our guide on asking your doctor about medication.
What to Tell the Prescriber
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Opioid Pain Relief and Naltrexone Use
Opioid pain medicine effects can be blocked by naltrexone.[5] This makes using opioids for pain hard. You need to talk to your doctors about this.
- Tell your naltrexone prescriber. Share details about any upcoming surgery, dental work, or new pain issues.
- Notify all involved clinicians. Let surgeons, dentists, anesthesiology teams, and emergency staff know you take naltrexone. Tell them well in advance.
- Ask for a coordinated plan. Request that your care team work together to manage your pain safely.
- Disclose immediately in emergencies. If you have urgent pain, tell the staff you take naltrexone right away. Do not wait to call your usual prescriber first.
Never alter or halt your naltrexone dosage without checking first. Speak with your prescriber before you make any changes to your medication plan.
Doctors may use regional pain methods or nonopioid options to manage discomfort. Your care team picks what works best for you. The facility must be ready for cardiopulmonary resuscitation.[5] Carry written details about your naltrexone use so providers can care for you well.[5]
Overdose Risk and When to Get Emergency Help
Naltrexone blocks the effects of opioids, but it does not protect you from an overdose if you use them anyway. After a while without using opioids, your body’s tolerance to them can drop.[5] Using the same amount you used before may be too much for your body to handle safely.
Trying to overcome the block or using opioids as the medication wears off can lead to a fatal overdose. This is a critical part of naltrexone safety and opioid use awareness. If you need to act fast, our guide to opioid overdose signs and treatment covers the rescue steps to take.
Act fast if you think someone is overdosing. Warning signs include not waking up or breathing that is slow, shallow, or has stopped. For a step-by-step look at what to do during a suspected opioid overdose, see our guide to naloxone access options.
- Call 911 right away. Do not wait to see if the person wakes up.
- Use naloxone if you have it. Follow the instructions on the package. Naloxone can reverse an opioid overdose, but its effects may wear off before the opioid does.[6]
- Stay with the person. Monitor their breathing until emergency responders arrive.
Always seek professional help after any suspected overdose.
If you or a loved one slips, do not call it a moral failure. It shows the current plan needs a change. Our guide on managing setbacks with support explains what to do after a relapse.
Safety Checks for Oral vs. Extended-Release Naltrexone
Naltrexone comes in two main types: an oral tablet and an extended-release injectable product.[7] Each form is given differently. Ask your care team about the safety questions for each. Our guide to naltrexone injection vs oral breaks down the side effects and safety details for each form.
Key differences appear in the table below. It does not tell you when opioid pain medicine is safe. It does not show when you can start naltrexone. A prescriber alone can set the right time based on your history.
| Feature | Oral Naltrexone | Extended-Release Injectable Naltrexone |
|---|---|---|
| Formulation | Tablet taken by mouth | Microsphere suspension for injection |
| Administration | Taken by the patient at home | Administered by a healthcare professional |
| Specific Risks | General medication side effects | Injection site reactions, which are distinct from tablet risks |
| Starting After Opioid Use | Ask your prescriber how long you must be opioid-free to avoid precipitating withdrawal[5] | Ask your prescriber how long you must be opioid-free to avoid precipitating withdrawal[5] |
| Duration of Opioid Blocking | Ask how long the blocking effect lasts and how it may affect pain care[5] | Ask how long the blocking effect lasts and how it may affect pain care[5] |
| Planning for Procedures or Urgent Pain | Discuss with your prescriber how to manage pain if you need opioid relief during a procedure or emergency[5] | Discuss with your prescriber how to manage pain if you need opioid relief during a procedure or emergency[5] |
A healthcare professional gives the extended-release injectable product.[5] This form has risks at the injection site. Reactions can happen where the shot goes in.
This drug blocks opioid receptors.[2] The effect can last past one dose. How long it lasts depends on the form and your situation.[5] Do not use this chart to judge if opioid pain medicine is safe for you.
Worried about how the medication impacts your body? Read our related guide to managing medication side effects for more details.
A Safer Move: Talk to Your Prescriber About Your Case
A quiz cannot say if opioids have left your body. It also cannot say if starting naltrexone is safe. Only a doctor can make that call. Use this check to plan your chat with your prescriber.
What Should I Discuss Before Starting Naltrexone?
This self-check is for information only and isn't a diagnosis. It cannot determine safe timing for medication.
Emergency Warning: If you have seizures, severe confusion, hallucinations, a high fever or racing heart during withdrawal, signs of an overdose, or thoughts of suicide or self-harm, get emergency help now—call 911 or go to an emergency room. For suicidal thoughts, call or text 988; call 911 or go to an emergency room for immediate danger or if you cannot stay safe.
Action Steps Before Starting
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Frequently Asked Questions
What happens if you take naltrexone with opioids?
If you still have opioids in your body, naltrexone can cause sudden withdrawal. You may feel sick to your stomach, vomit, or have diarrhea. You might also have muscle aches and anxiety.[8] Do not try to guess if this is safe. Call your prescriber right away. If you have severe symptoms, call 911 or go to the nearest emergency room now.
What drugs should not be taken with naltrexone?
Tell your prescriber and pharmacist about all your medicines. Include prescription drugs, over-the-counter items, and other substances. Some products that do not look like painkillers may still contain opioids, such as certain cough syrups, anti-diarrheal medicines, or combination pain relievers. A clinician or pharmacist should check your complete medication list to identify these interactions, rather than relying on this article as an exhaustive list.
Does naltrexone block opioid receptors?
Yes, naltrexone blocks opioid effects at receptors.[2] It does not activate them. The drug does not remove opioids from your body. It also does not make using opioids safe. Never try to beat the block by taking more opioids.
How does naltrexone help with opioid addiction?
Naltrexone is one of the medications approved to treat opioid use disorder.[2] In the context of naltrexone and opioid use disorder, the medication works by blocking opioid receptors so that opioid drugs can no longer cause feelings of pleasure.[2] This differs from its role in alcohol use disorder, where it is also approved to help reduce cravings and heavy drinking.[2] Naltrexone is one treatment option among others, and it is often used alongside counseling or therapy. A prescriber must assess your specific health history and goals to determine if it is appropriate for you. They can help you compare this option with other treatments without providing specific dosing instructions here.
Why don't doctors like naltrexone?
Doctors do not have a general dislike for naltrexone. Clinicians look at your goals and health history first. They may delay starting naltrexone or choose another treatment if there is a risk of precipitated withdrawal because opioids are still in your body, if you need ongoing opioid pain treatment, or if other factors fit your specific treatment goals better. If a provider suggests a different option, ask why they chose it for you. This helps you understand the plan for your care.
Can I take pain meds while on naltrexone?
Do not assume opioid pain meds will work normally on naltrexone. The blocking effect can last for different amounts of time.[5] It depends on the form of the drug and your body. Do not stop or change naltrexone on your own. Talk to your prescriber first. Tell any doctor treating your pain that you take naltrexone so they can pick safer options.
