Is Naltrexone Safe to Take During Pregnancy?

Alcohol or opioid use during pregnancy is linked to several risks for you and your baby. So if you’re pregnant and you have an alcohol use disorder (AUD) or opioid use disorder (OUD), seeking or continuing treatment is important.

Naltrexone (Vivitrol) is a medication that treats AUD and OUD. But is naltrexone safe in pregnancy? It all depends on your individual risks. 

What is naltrexone?

Naltrexone belongs to a group of medications called opioid antagonists. It’s available as an oral tablet and intramuscular (IM) injection. The IM injection is available as brand-name Vivitrol. 

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Both formulations are approved to treat AUD. IM naltrexone is also approved to treat OUD. Naltrexone tablets are usually taken once daily for AUD. The IM injection is usually administered at your doctor’s office every 4 weeks.

Naltrexone works by occupying the same chemical binding sites as opioids, which are called opioid receptors. Alcohol has an effect on opioid receptors as well. By blocking these receptors, naltrexone decreases the positive, “euphoric” effects you may feel after taking opioids or drinking alcohol. This reduces cravings for these substances.

Is naltrexone safe in pregnancy?

Compared to continued alcohol or opioid use, naltrexone may be safe during pregnancy. But it depends on your individual situation.

Alcohol use disorder

In general, medications aren't first-choice treatment options for AUD. Non-medication treatments are usually recommended first. These include individual therapy, couples and family counseling, and support groups like Alcoholics Anonymous. 

But if these aren’t enough to help you stop drinking, naltrexone may be an option. This is especially true if you're taking naltrexone before becoming pregnant and tolerating it well.

Opioid use disorder

Medications are considered a first-choice treatment option for OUD. But methadone (Methadose) and buprenorphine (Subutex) are typically preferred over naltrexone. However, if you were receiving naltrexone before becoming pregnant, it may be reasonable to continue it.

Naltrexone isn’t a first-choice medication for OUD for a couple reasons. One is that you have to be opioid-free for 7 to 10 days before starting naltrexone. This is because naltrexone may worsen withdrawal symptoms after stopping opioids. And some withdrawal symptoms, like heart palpitations and loss of appetite, could negatively affect your pregnancy.

Additionally, you’re at a high risk of relapse during this 7- to 10-day period without opioids. Relapsing to opioids can cause problems with your pregnancy. So it should be avoided at all costs. Since methadone and buprenorphine don’t require you to stop opioids in advance, they may be better options.

What does the research say about naltrexone during pregnancy?

We don’t have much research on naltrexone for AUD in pregnancy. We have more studies on naltrexone for OUD during pregnancy. But some of this research was done with a naltrexone implant product that isn’t commercially available. 

Still, here’s what we know:

• In a study of 230 pregnant women, oral naltrexone didn’t increase the risk of miscarriage, stillbirth, or birth defects when compared to methadone or buprenorphine. And it was less likely to cause neonatal abstinence syndrome (NAS). NAS happens when a baby has opioid withdrawal after they’re born (due to exposure to opioids during pregnancy).

• A study of close to 2,000 women with OUD found that ectopic pregnancies were more common in the group using implantable naltrexone versus those using methadone or buprenorphine. The naltrexone group also had more complications during pregnancy compared to pregnant women not receiving OUD medication. But there was no difference in complications compared to buprenorphine or methadone. Complications during labor were similar among all the groups.

• In a small study, babies exposed to naltrexone in the womb were born smaller, spent more time in the hospital, and had a higher rate of NAS than babies who weren’t exposed to any OUD medications. However, naltrexone-exposed babies had shorter hospital stays and lower rates of NAS compared to methadone and buprenorphine-exposed babies.

Good to know: We don’t know what (if any) the long-term effects of naltrexone exposure in the womb are. But we do know that there are long-term risks for babies exposed to alcohol and opioids in the womb. Heavy drinking while pregnant can put your pregnancy at risk, cause birth defects, and may even cause developmental problems for your baby later in life. Taking opioids during pregnancy may also lead to birth defects. It can also cause NAS, which has been linked to negative developmental problems for your baby (though the research is conflicting).

Can you take naltrexone while breastfeeding?

Oral and IM naltrexone may be safe to use during breastfeeding. We don’t have much research on this, though, so you and your healthcare team should discuss whether the benefits outweigh the risks.

Are there other medication options for treating AUD and OUD during pregnancy?

Other medications besides naltrexone are FDA approved to treat AUD and OUD. We’ll cover the options for treating each condition during pregnancy below.

AUD medications in pregnancy

As mentioned previously, non-medication treatment options like therapy and support groups are first-choice treatment options for AUD in pregnancy. But if you’re unable to stop drinking alcohol with these methods, medications may be a good choice.

Acamprosate and disulfiram are two other oral medications that are FDA approved for AUD. Like naltrexone, we don't know exactly how safe they are in pregnancy.

However, the minimal research we do have suggests that acamprosate may be safe during pregnancy. Disulfiram studies have mixed results, so its use may be more risky. If medication is needed, naltrexone or acamprosate may be your best options.

OUD medications in pregnancy

As mentioned previously, medications are first-choice treatment options for OUD (along with counseling and mental health support). But methadone and buprenorphine are typically preferred over naltrexone. 

One exception may be if you’re receiving naltrexone before becoming pregnant. In this case, it may be best to continue taking naltrexone versus switching to methadone or buprenorphine.

However, if you’re taking naltrexone, it likely won’t be safe to receive opioids during your pregnancy or labor. Naltrexone can make you more sensitive to negative opioid effects. Additionally, the pain relief that opioids usually provide may be blocked by naltrexone.

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Written by:

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She was a full-time clinical professor in the pharmacy practice department at D’Youville School of Pharmacy before subsequently joining the faculty of the pharmacy practice department at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

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:

Adriena Beatty D.O., MBA, CPE

Adriena Beatty, DO, MBA, CPE, is an Army veteran and board-certified obstetrician and gynecologist with over 20 years of experience. She is a graduate from Tuskegee University with a degree in chemical engineering and chemistry.

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