4 Naltrexone Interactions to Watch Out for

More than 2.7 million people in the U.S. had an opioid use disorder (OUD) in 2020. And 28.3 million had an alcohol use disorder (AUD). OUD and AUD are substance use disorders. Someone with a substance use disorder is physically, mentally, or emotionally dependent on drugs or alcohol. And they experience problems in their day-to-day lives due to this dependence.

People who have OUD or AUD may need treatment. Naltrexone (Vivitrol) is one of the FDA-approved medications to treat OUD and AUD. It’s part of a group of medications called opioid antagonists. Naltrexone comes as an oral tablet or an intramuscular (IM) injection. The tablet is usually taken once a day. The injection is administered by a healthcare provider once a month. 

Naltrexone can interact with other medications, especially opioid medications. Below, we’ll lay out what you need to know about this interaction and others. But this isn’t a complete list of naltrexone interactions. Give your healthcare provider and pharmacist an updated medication list before starting naltrexone. With this list, they can help you check for possible naltrexone interactions. 

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1. Prescription opioid medications

Opioid medications are typically used to treat different types of pain. They’re all controlled substances. This means they’re more likely than non-controlled medications to cause dependence and addiction. They also have restrictions on how they’re filled. Examples include: 

• Hydrocodone/acetaminophen

• Oxycodone (Roxicodone, Oxycontin) 

• Morphine (MS Contin)

• Tramadol (Ultram)

• Fentanyl products including the patch, tablets (Fentora), and lozenge (Actiq)

• Meperidine

• Buprenorphine (Belbuca, Subutex, Butrans)

• Methadone (Methadose, Dolophine)

Opioids work by changing how the brain interprets and responds to pain. They do this by blocking pain signals in the body. So if you’re hurting you won’t feel it as much. 

Naltrexone works by blocking the rewarding effects of opioids and alcohol. It does this by blocking the areas of the brain where opioids attach, called opioid receptors. If you’re taking opioids when you start naltrexone, opioid withdrawal symptoms can occur. Common opioid withdrawal symptoms include nausea and vomiting, irritability, and sweating. You may also experience a runny nose, anxiety, and muscle aches. If you’re starting naltrexone, stop taking opioids at least 7 to 10 days beforehand to avoid withdrawal.

If you’re taking naltrexone for OUD and you relapse to opioids, stop naltrexone and contact your healthcare provider. It’s also important to know that you may be more sensitive to opioids after stopping naltrexone. This means that lower opioid doses than what you’ve tolerated in the past may now be too much for you. Taking opioids could lead to an overdose, which can be fatal. 

If you have an upcoming surgery (even dental surgeries), let your surgeon know that you take naltrexone. If you have injuries that require pain medication, your healthcare provider may suggest non-opioid pain medications. Examples include over-the-counter (OTC) medications like ibuprofen (Advil, Motrin) or acetaminophen (Tylenol). But if opioids are required, they may recommend a different medication than naltrexone to treat OUD. Examples include buprenorphine or methadone.

2. Some cough medications

Some prescription-only cough medications contain opioids. Examples of these medications include promethazine/codeine and hydrocodone/homatropine (Hydromet, Hycodan).

If you start naltrexone while taking an opioid-containing cough product, withdrawal symptoms may occur. This is because naltrexone can block the effects of these opioids, leading to uncomfortable withdrawal symptoms. If you’re starting naltrexone, you should stop any opioid product at least 7 to 10 days beforehand to avoid withdrawal.

If you take naltrexone and have a bothersome cough, talk to your healthcare provider. There are other cough medications, like guaifenesin (Mucinex), that may work for you. Your provider can help you select a safe and effective cough medication.

3. Some antidiarrheal medications

Some prescription-only diarrhea treatments contain opioids. Examples include diphenoxylate/atropine (Lomotil) and opium tincture. Loperamide (Imodium-AD) is also considered an opioid and is OTC.

If you’re taking any of these antidiarrheals, you’ll need to wait 7 to 10 days before starting naltrexone. The opioid component of these medications can interact with naltrexone and cause withdrawal symptoms. Luckily, there are some OTC options that may work for you, including bismuth subsalicylate (Pepto-Bismol). 

4. Alcohol

It’s best to avoid alcohol while taking naltrexone. Even though taking naltrexone and alcohol together doesn’t cause significant harm, alcohol itself can be very harmful.

Naltrexone reduces cravings by blocking the rewarding effects of alcohol. But it doesn’t lessen alcohol’s effects on the body. So if you continue to drink, short-term effects of alcohol are still possible. These include dehydration, slowed brain functioning, and accidental injuries. Long-term effects, like depression, anxiety, and memory impairment, are also possible. Keeping away from alcohol has many benefits for your body as well.

Talk to your healthcare provider if you're considering drinking alcohol while taking naltrexone. They can further discuss the risks of this combination with you.

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Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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If you or someone you know struggles with substance use, help is available. Call SAMHSA’s National Helpline at 1-800-662-4357 to learn about resources in your area.