Promethazine

Date: June 2025, Version 4.0

Quick read

Promethazine can be used during pregnancy and is a recommended treatment for pregnancy sickness.

What is it?

Promethazine (Phenergan®, Sominex®) is a sedating (drowsy) antihistamine that is used to treat nausea and vomiting, some allergies, and for short-term treatment of some sleep problems.

Benefits

What are the benefits of using promethazine in pregnancy?

Promethazine can help with the symptoms of pregnancy sickness and allow you to live your normal life. For more details, please see the bumps leaflets on treating Pregnancy sickness and hyperemesis gravidarum.

Promethazine can also help you feel better if you have unpleasant symptoms caused by allergy.

If you are having problems sleeping, promethazine can be taken for a few days to help.

Risks

Are there any risks of using promethazine during pregnancy?

No. Promethazine is commonly used during pregnancy and there are no concerns that it harms your unborn baby.

Alternatives

Are there any alternatives to using promethazine?

Possibly. Other medicines can be used to treat pregnancy sickness and allergies. Sleep problems can sometimes be improved without a medicine. However, if promethazine is recommended as treatment during pregnancy, this is because your doctor thinks it is the best drug for you. If you have any questions about a medicine, you can speak to your doctor or midwife.

No treatment

What if I prefer not to take using promethazine?

Your doctor will only prescribe medicines when necessary and will be happy to talk to you about any concerns that you might have.

Will my baby need extra monitoring?

Most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects as part of their routine antenatal care. Using promethazine in pregnancy would not normally require extra monitoring of your baby.

Are there any risks to my baby if the father has taken promethazine?

We do not expect any increased risk to your baby if the father takes promethazine.

Who can I talk to if I have questions?

If you have any questions regarding the information in this leaflet, please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.

How can I help to improve drug safety information for pregnant women in the future?

Our online reporting system (MyBump Portal) allows women who are currently pregnant to create a secure record of their pregnancy, collected through a series of questionnaires. You will be asked to enter information about your health, whether or not you take any medicines, your pregnancy outcome and your child's development. You can update your details at any time during pregnancy or afterwards. This information will help us better understand how medicines affect the health of pregnant women and their babies. Please visit the MyBump Portal to register.

General information
Sadly, miscarriage and birth defects can occur in any pregnancy.

Miscarriage occurs in about 1 in every 5 pregnancies, and 1 in every 40 babies are born with a birth defect. This is called the ‘background risk’ and happens whether medication is taken or not.

Most medicines cross the placenta and reach the baby. For many medications this is not a problem. However, some medicines can affect a baby’s growth and development.

If you take regular medication and are planning to conceive, you should discuss whether your medicine is safe to continue with your doctor/health care team before becoming pregnant. If you have an unplanned pregnancy while taking a medicine, you should tell your doctor as soon as possible.

If a new medicine is suggested for you during pregnancy, please make sure that the person prescribing it knows that you are pregnant. If you have any concerns about a medicine, you can check with your doctor, midwife or pharmacist.

Our Bumps information leaflets provide information about the effects of medicines in pregnancy so that you can decide, together with your healthcare provider, what is best for you and your baby.