Histadoxylamine Succinate

THE SAFETY OF UNISOM (DOXYLAMINE SUCCINATE) DURING PREGNANCY OR BREASTFEEDING

The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

THIS MEDICATION MAY CAUSE HARM TO YOUR BABY:

Ask your doctor before using Unisom (doxylamine succinate) while pregnant or breastfeeding. Most studies that have analyzed the safety of doxylamine in pregnancy have looked at expecting moms who took a combination tablet containing doxylamine succinate and pyridoxine. The combination tablet has not been associated with a higher risk of birth defects when taken during pregnancy. Taking any antihistamine, such as Unisom, during the last 2 weeks of pregnancy may cause abnormal eye development in your baby, which could lead to blindness.

What is Unisom (doxylamine succinate)?

Unisom is taken to help people fall asleep. Unisom SleepTabs are tablets containing the active ingredient doxylamine succinate. Unisom is also available as mini-capsules, gel capsules, dissolvable tablets, and liquid. However, these other forms of Unisom do not contain doxylamine succinate. Instead, they contain diphenhydramine. This medication report will focus on the safety of Unisom SleepTabs (doxylamine succinate) during pregnancy. All Unisom products can be purchased without a prescription.

What is Unisom (doxylamine succinate) used to treat?

Unisom is used to treat sleeping problems or insomnia. Insomnia is characterized by difficulty falling asleep or staying asleep. People with insomnia may also wake up earlier than expected and not be able to return to sleep. Short-term insomnia can occur during periods of stress and may last for a few nights, but long-term insomnia can last for several months. People with insomnia often experience fatigue, lack of energy, difficulty concentrating, and changes in mood. You can read about insomnia during pregnancy here and ways to manage insomnia during pregnancy here.

How does Unisom (doxylamine succinate) work?

Unisom is a type of antihistamine, which means that it blocks some of the effects of histamine. Antihistamines are typically used to treat allergies. Doxylamine succinate is not used for this purpose because it has a side effect of extreme sleepiness. This side effect makes Unisom helpful for people who have insomnia. Doxylamine succinate also can reduce symptoms of nausea and vomiting.

If I am taking Unisom (doxylamine succinate), can it harm my baby?

Always ask your doctor before using Unisom if you are pregnant. Most studies that have looked at the safety of doxylamine during pregnancy have analyzed expecting moms who took a combination medication consisting of doxylamine succinate and pyridoxine. Doxylamine succinate and pyridoxine (brand name Diclegis) was approved by the FDA in 2013 for the treatment of nausea and vomiting during pregnancy in expecting moms whose symptoms do not improve with dietary or lifestyle changes. Based on current data, using doxylamine succinate and pyridoxine during pregnancy has not been associated with a higher risk of birth defects. The combination of doxylamine succinate and pyridoxine is recommended by the American College of Obstetricians and Gynecologists (ACOG) and the Association of Professors of Gynecology and Obstetrics (APGO) for expecting moms whose nausea and vomiting symptoms are not improved by diet and lifestyle changes. The use of doxylamine succinate and pyridoxine in pregnancy has been studied in more than 200,000 expecting moms, which is more than any other medication in pregnancy. The numerous studies involving doxylamine succinate and pyridoxine have supported the approval of this medication for use in pregnant women suffering from nausea and vomiting. Doxylamine succinate is considered compatible with pregnancy by some experts.

The dose of doxylamine succinate in Unisom (25 mg) is higher than the dose found in the combination tablet of doxylamine succinate and pyridoxine (10 mg), meaning that your baby will be exposed to more of the medication. Unisom can cause daytime drowsiness and dizziness and may not be recommended for some expecting moms. Your doctor will evaluate the potential risks of Unisom and determine if the medication is safe for both you and your baby.

The history of doxylamine succinate and pyridoxine use in pregnancy:

The ingredients doxylamine succinate and pyridoxine were originally contained in a combination product, called Bendectin, that was marketed in 1956 for treating nausea and vomiting in pregnancy. Bendectin contained a third ingredient, dicyclomine, which was later removed from the product. This medication was widely prescribed, with up to 25% of expecting moms in the US taking Bendectin at the height of its use. During the 1960s and 1970s, letters to medical journals, law firms, and the media began to report an association between the use of Bendectin and birth defects. By 1983, over 300 lawsuits were pending, which claimed that Bendectin caused birth defects. However, most cases lacked scientific evidence for these claims. The manufacturer of Bendectin discontinued the product in 1983 due to financial concerns. The company’s insurance premiums were becoming unaffordable after many of these lawsuits.

Evidence on the use of doxylamine succinate and pyridoxine during pregnancy:

In September 1980, the Food and Drug Administration (FDA) Fertility and Maternal Health Drugs Advisory Committee reviewed 13 studies, including 2 studies that suggested that Bendectin (doxylamine succinate and pyridoxine) was associated with birth defects and 11 that found no association between Bendectin and birth defects. The committee concluded that, overall, the data did not show that the use of Bendectin during pregnancy was associated with birth defects.

Two additional reviews looked at data related to doxylamine succinate and pyridoxine use during pregnancy. One of the reviews looked at 17 different studies published between 1963 and 1985 and found no increased risk of birth defects in expecting moms who used doxylamine succinate and pyridoxine during the first trimester of pregnancy. The other review looked at 27 different studies published between 1963 and 1991 and found no increased risk of birth defects in expecting moms who used doxylamine succinate and pyridoxine during the first trimester of pregnancy.

The data maintained by the Centers for Disease Control and Prevention also did not support an association between Bendectin (doxylamine succinate and pyridoxine) use and birth defects. The rate of birth defects observed during the height of Bendectin use (1978 to 1980) was the same as the time period after Bendectin was withdrawn from the market (1985 to 1987).

Possible risk with antihistamine use:

A higher risk of retrolental fibroplasia (a condition causing abnormal eye development, which could lead to blindness) was found in babies when moms took any antihistamine during the last 2 weeks of pregnancy. 

Bottom line: Always ask your doctor before using Unisom during pregnancy. The combination of doxylamine succinate and pyridoxine has been studied extensively in pregnancy and is approved by the FDA for the treatment of nausea and vomiting during pregnancy. Based on current data, using doxylamine succinate and pyridoxine during pregnancy has not been associated with a higher risk of birth defects. Unisom contains a higher dose of doxylamine succinate than the combination tablet of doxylamine succinate and pyridoxine and will expose your baby to more of the drug. Additionally, taking any antihistamine during the last 2 weeks of pregnancy has been associated with abnormal eye development in the baby. Your doctor will decide if Unisom is safe for you and your baby.

If I am taking Unisom (doxylamine succinate) and become pregnant, what should I do?

If you become pregnant while taking Unisom, you should contact your doctor immediately. Your doctor will decide if Unisom should be continued, or if an alternative medication should be used.

If I am taking Unisom (doxylamine succinate), can I safely breastfeed my baby?

Ask your doctor before using Unisom if you are breastfeeding. The use of the combination tablet containing doxylamine succinate and pyridoxine is not recommended for treating breastfeeding mom
s. Doxylamine succinate is expected to pass into breast milk. Reports of sleepiness, irritability, and excitement have been described in breastfed babies supposedly exposed to doxylamine succinate through breast milk. Babies with breathing problems may be particularly vulnerable to side effects of sleepiness or worsening breathing problems. Some experts have suggested that small occasional doses of doxylamine are unlikely to cause side effects in the breastfed baby. However, higher doses or doses taken for longer time periods may lead to sleepiness. If your doctor determines that Unisom is medically necessary, you should monitor your baby for signs of sleepiness, irritability, or other side effects and immediately report them to your doctor.

Bottom line: Ask your doctor before using Unisom if you are breastfeeding. The combination tablet containing doxylamine succinate and pyridoxine is not recommended for use in breastfeeding moms. Doxylamine succinate is expected to pass into breast milk and may cause sleepiness, irritability, or excitement in breastfed babies.

If I am taking Unisom (doxylamine succinate), will it be more difficult to get pregnant?

No studies have looked at the effects of doxylamine succinate on fertility in women. However, some evidence from animal studies has indicated that antihistamines may impair fertility in men. 

If I am taking Unisom (doxylamine succinate), what should I know?

Ask your doctor before using Unisom if you are pregnant or breastfeeding.

The combination doxylamine succinate and pyridoxine has been approved by the FDA for treating nausea and vomiting during pregnancy. Based on current data, taking the combination of doxylamine succinate and pyridoxine during pregnancy has not been associated with a higher risk of birth defects. The dose of doxylamine succinate in Unisom is higher than the dose contained in the combination tablet and may increase your baby’s exposure to the drug. Additionally, taking any antihistamine during the last 2 weeks of pregnancy could lead to abnormal eye development in the baby. Your doctor will determine if Unisom is safe for you and your baby.

The combination doxylamine succinate and pyridoxine is not recommended for use in breastfeeding moms. Doxylamine succinate is expected to pass into breast milk and can cause sleepiness, irritability, and excitement in the breastfed baby.

If I am taking any medication, what should I know?

This report provides a summary of available information about the use of Unisom (doxylamine succinate) during pregnancy and breastfeeding. Content is from the product label unless otherwise indicated.

You may find Pregistry's expert report about insomnia and the various medications used to treat insomnia here   Additional information can also be found in the resources below. 

For more information about Unisom (doxylamine succinate) during and after pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or check the following links:

Unisom: Our Products.

National Sleep Foundation: What is insomnia?

Mayo Clinic Staff: Insomnia

Read the whole report
General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.