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Nausea Medications During Pregnancy: Which Are Safe to Take?

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMPDaphne Berryhill, RPh
Written by Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP | Reviewed by Daphne Berryhill, RPh
Updated on September 4, 2024

Key takeaways:

  • If you need medication to relieve nausea and vomiting during pregnancy, there are a few over-the-counter (OTC) nausea medications. Examples include pyridoxine (vitamin B6), doxylamine (Unisom), and other oral antihistamines like diphenhydramine (Benadryl).

  • Some people may need a prescription nausea medication during pregnancy if OTC options don't work. Examples include doxylamine / pyridoxine (Diclegis, Bonjesta), metoclopramide (Reglan), and ondansetron (Zofran).

  • Always talk to your pregnancy care team before trying morning sickness medications.

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If you’re pregnant and feeling nauseated, you’re not alone. It’s estimated that up to 80% of people experience nausea while pregnant. It most often happens during the first trimester. And while nausea during pregnancy is often called "morning sickness," this term is misleading. Nausea can happen any time of day, making it difficult to eat a healthy diet or take your prenatal vitamins. In more severe cases, vomiting can lead to weight loss and dehydration.

Sometimes, changing your diet and avoiding triggers can improve nausea. But if it's not enough, over-the-counter (OTC) or prescription nausea medications for pregnancy can help.

OTC nausea medications during pregnancy

If lifestyle changes don't work (more on this later), or your nausea is severe, some OTC and prescription medications are safe to take during pregnancy. Always talk to your pregnancy care team before starting a new medication while pregnant.

Safe OTC nausea medications during pregnancy include pyridoxine (vitamin B6), doxylamine (Unisom), and more. We’ll cover these options below.

Pyridoxine

Though prenatal vitamins often contain pyridoxine (vitamin B6), taking it as an additional supplement may help nausea. This is because low levels of vitamin B6 in the body can cause nausea, so taking it as a supplement can help relieve nausea. In fact, the ACOG recommends pyridoxine supplements as a first-choice option for nausea and vomiting during pregnancy.

Overall, we don’t have many well-designed studies on how well pyridoxine works during pregnancy. Available research shows mixed results on whether pyridoxine is effective at treating nausea and vomiting. But it’s considered safe when taken correctly. In one large review of different medications used for pregnancy-related nausea and vomiting, pyridoxine didn’t raise the risk of birth defects

Pyridoxine is usually tolerated well at normal doses. The recommended dose during pregnancy is 10 mg to 25 mg by mouth three to four times a day. But at high doses, side effects like tingling in the hands and feet (neuropathy) can occur.

Doxylamine

Doxylamine is an antihistamine that can be used off-label to treat pregnancy-related nausea and vomiting. Doxylamine works by blocking certain chemicals (histamines) that may be involved in causing nausea. It's also a sleep-aid, so it's often found in the sleep medication section of pharmacies.

The ACOG recommends combining doxylamine and pyridoxine when pyridoxine alone doesn’t relieve your nausea. In fact, there’s a combination pill (Diclegis, Bonjesta) that contains both medications, but it’s only available by prescription.

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We don’t have much research comparing the combination of doxylamine and pyridoxine to pyridoxine alone. But some research shows that the combination is better than placebo (a pill with nothing in it) at relieving nausea. However, other research hasn’t found this combination to be effective.

Although the effectiveness of doxylamine and pyridoxine is up for debate, it’s considered safe during pregnancy. Drowsiness and dizziness are the most common side effects of doxylamine. Other side effects you might notice include dry mouth and headache.

Although a prescription-only combination pill exists, your pregnancy provider may recommend taking doxylamine and pyridoxine pills individually, since these can be found OTC and are typically less expensive. Just make sure to follow their instructions closely for how to take these medications. A common dose is 10 mg to 25 mg of pyridoxine and 12.5 mg of doxylamine taken 3 to 4 times daily. You may need to cut the tablets in half with a pill splitter to get the correct dose.

Other antihistamines, like diphenhydramine

Meclizine (Antivert), diphenhydramine (Benadryl), and dimenhydrinate (Dramamine) are other antihistamines that may relieve pregnancy-related nausea “off-label”. But we don’t have a lot of research on how well these medications work for this use. Still, they’re considered safe when used at appropriate doses. Like doxylamine, common side effects of these medications include sleepiness and dizziness.

Common doses for these medications are:

If you’re taking doxylamine, talk to your pregnancy provider before taking one of these antihistamines listed here. Taking multiple antihistamines can lead to excessive drowsiness.

Prescription nausea medications during pregnancy

If OTC medications don’t help, your pregnancy care team might recommend a prescription medication. Below, we’ll discuss the different prescription options available.

Doxylamine / pyridoxine combination pill

As discussed, pyridoxine and doxylamine are available as a combination pill. It’s available as generic and brand-name products called Diclegis and Bonjesta.

Depending on which product you’re taking, your dose may vary. Diclegis contains 10 mg each of doxylamine and pyridoxine. The starting dose is 2 tablets by mouth at bedtime on an empty stomach (day 1). Then, typical dosing instructions are below:

  • If your symptoms don't improve on day 2 , you can add 1 tablet in the morning on day 3.

  • If you're still having symptoms by day 4, , you can take up to 4 tablets per day: 1 tablet in the morning, 1 in the afternoon, and 2 at bedtime. The maximum daily dose is 4 tablets.

Bonjesta contains 20 mg each of doxylamine and pyridoxine. The typical dose is 1 tablet by mouth at bedtime on an empty stomach. If your symptoms don't get better after 2 days, you can increase to 1 tablet twice daily (1 in the morning and 1 at bedtime). The maximum daily dose is 2 tablets.

Diclegis is available as a generic, but Bonjesta isn’t. Both these combination pills are typically more expensive than purchasing doxylamine and pyridoxine OTC as individual medications. But if you have insurance, it’s possible that they may cover the cost. You can call your insurance provider to find out.

Dopamine antagonists, such as metoclopramide

Dopamine antagonists are considered second-choice prescription medications for nausea and vomiting during pregnancy. Promethazine (Promethegan) and metoclopramide (Reglan) are dopamine antagonists. They relieve nausea by blocking the effects of a chemical called dopamine, which is involved in causing nausea.

Studies have shown these medications improve nausea and vomiting in pregnancy, and metoclopramide is often preferred over promethazine. At appropriate doses, they’re typically considered safe in pregnancy and aren't linked to birth defects.

The usual dose of promethazine for pregnancy related nausea is 12.5 mg to 25 mg every 4 to 6 hours, taken orally or rectally (as a suppository). In severe cases of nausea and vomiting, it can be given intravenously (IV). You’ll likely feel drowsy after taking promethazine. Avoid driving and other activities that require concentration until you know how it affects you. Other possible side effects include dizziness, dry mouth, and confusion.

A common metoclopramide dose for nausea in pregnancy is 5 mg to 10 mg by mouth every 6 to 8 hours. Common side effects include tiredness and restlessness. 

More seriously, consistently taking metoclopramide and promethazine can cause serious movement problems, such as a movement disorder called tardive dyskinesia. This condition causes repetitive movements of your body that you can’t control. Stop taking these medications and call a healthcare professional if you experience this.

Serotonin antagonists, such as ondansetron

Selective serotonin receptor (5-HT3) antagonists relieve nausea by blocking certain serotonin receptors (binding sites) throughout the body. Serotonin is a chemical that plays a role in creating feelings of nausea. Ondansetron (Zofran) is one example. Like metoclopramide and promethazine, It's considered a second-choice option for pregnancy-related nausea and vomiting.

Ondansetron has been found to be effective at treating nausea and vomiting, and it may be more effective than other nausea treatments. But it’s typically only used when first-choice treatments, such as doxylamine / pyridoxine, don’t work. A common ondansetron dose for pregnancy-related nausea and vomiting is 4 mg every 8 hours.

Additionally, ondansetron is typically considered safe in pregnancy. A large study of over 88,000 infants exposed to ondansetron in the first trimester, there was no greater risk of heart defects. There was slightly more risk for developing a cleft palate (an opening in the upper lip or roof of the mouth). However, this possible risk hasn’t been confirmed.

The most common side effects of ondansetron are headaches, constipation, and tiredness. More serious side effects are also possible. For example, ondansetron can cause abnormal heart rhythms. If you notice a change in your heart beat, lightheadedness, or fainting, stop ondansetron and contact your healthcare professional.

What diet and lifestyle changes can you try before taking medications?

Sometimes, changes to your diet and lifestyle can help relieve nausea. So the American College of Obstetricians and Gynecologists (ACOG) recommends trying non-medication options first. Here, we’ll discuss vitamins, supplements, and diet changes that might ease nausea. For more information on alternative treatments, check out our in-depth guide on morning sickness.

Vitamins and supplements

Taking a prenatal vitamin that contains at least 10 mg of vitamin B6 can help reduce your risk of nausea and vomiting during pregnancy. This may be because low vitamin B6 levels has been found to increase your risk of morning sickness. 

Take your prenatal vitamin at the time of day when you’re least nauseated. You can also try taking it with a small meal.

Some prenatal vitamins contain iron, which may cause more nausea. But before skipping out on iron, talk to your pregnancy care team about whether you can take a prenatal vitamin without iron while you’re experiencing nausea.

Ginger is a natural supplement that may also relieve nausea. You can find OTC ginger in capsules, teas, or candies. Some research shows that consuming 1,000 mg (divided throughout the day) can help ease nausea

Adjusting your diet

Changing your diet may help relieve pregnancy-related nausea. Try eating small meals throughout the day. This keeps food in your stomach, which may prevent nausea. But keep in mind that spicy, greasy, and strong-smelling foods may make you more nauseated. Bland foods, like bananas and rice, are easier on your stomach. And some studies show that having a healthy amount of protein in your diet can relieve nausea.

Drinking water

Drinking enough water can also help decrease nausea because dehydration makes nausea worse. Your body needs more water when you’re pregnant. Aim for about 8 to 12 cups of water a day.

When you’re experiencing nausea, try chewing gum or sucking on a piece of hard candy before you eat or drink water. If you’re having trouble drinking water, add fruit or a little juice to your water to create flavor. And consider eating fruits and vegetables with high water content. Examples include strawberries, melons, and cucumbers.

Frequently asked questions

Acupressure is the practice of putting pressure on specific points of the body. These are the same areas used for acupuncture. But acupuncture uses needles instead of pressure.

A commonly tested location for acupressure treatment is a small point above the wrist on the underside of the arm (called “P6”). But studies have shown mixed results on how well acupressure works.

Morning sickness usually starts between your 4th to 9th week of pregnancy. For most people, morning sickness improves by 16 weeks. But for some people, morning sickness may last longer. 

Yes, for some people, morning sickness during pregnancy causes nausea, but not vomiting.

Up to 3% of pregnant people experience a severe form of nausea and vomiting during pregnancy. It’s called hyperemesis gravidarum. It typically involves frequent vomiting and weight loss. If you're experiencing hyperemesis gravidarum, talk to a healthcare professional. You may need to be hospitalized, or treated in a clinic, to manage weight loss or dehydration from excessive vomiting. They may give you IV fluids to rehydrate you. They may also give you IV or rectal nausea medications if you can't keep oral medications down.

The bottom line

If you’re experiencing nausea and vomiting during pregnancy, diet and lifestyle changes may help. But if these aren’t enough, taking nausea medications during pregnancy may be an option. Over-the-counter (OTC) or prescription medications are available. OTC pyridoxine (vitamin B6) supplements are often tried first. Doxylamine (Unisom) can be added if pyridoxine alone isn’t enough. Doxylamine and pyridoxine are found separately OTC, but combination pills (Diclegis, Bonjesta) are available as well. However, they’re prescription only. Other OTC antihistamines like diphenhydramine (Benadryl) and meclizine (Antivert) are possible options as well. 

If OTC medications don’t work, your pregnancy care team may recommend a prescription nausea medication. Examples include metoclopramide (Reglan), promethazine (Promethegan), and ondansetron (Zofran).

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Why trust our experts?

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She currently practices as a clinical pharmacist at Buffalo General Medical Center.
Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.
Daphne Berryhill, RPh, has two decades of experience as a clinical pharmacist. She spent most of her career in the Chicago area practicing in-home infusion.

References

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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