Calcium channel blockers

Date: December 2022, Version 2.0

Quick read

Calcium channel blockers can be used in pregnancy to treat angina and high blood pressure.

What are they?

Nine calcium channel blockers are used in the UK: amlodipine (Istin®), diltiazem (Tildiem®, Adizem®, Angitil®, Dilcardia®, Slozem®, Uard®, Viazem®, Zemtard®), felodipine (Cardioplen®, Delofine®, Felotens®, Folpik®, Neofel®, Parmid®, Vascalpha®), lacidipine (Motens®, Molap®), lercanidipine (Zanidip®), nicardipine (Cardene®), nifedipine (Adipine®, Nifedipress®, Tensipine®, Dexipress®, Valni®, Adalat®, Adanif®, Neozipine®, Nidef®, Fortipine®), nimodipine (Nimotop®), and verapamil (Half Securon®, Vera-Til®, Verapress®, Securon®).

Calcium channel blockers are mainly used to treat angina and high blood pressure.

Nifedipine is used to treat Reynaud’s phenomenon (a circulatory problem), verapamil can also be used to treat an arrhythmia (irregular heartbeat) and to prevent cluster headaches, and diltiazem cream might be prescribed to treat anal fissure.


What are the benefits of using a calcium channel blocker in pregnancy?

Calcium channel blockers can prevent the pregnancy complications caused by high blood pressure and a related condition called pre-eclampsia. These complications include preterm birth, low infant birth weight, and illness in the mother and baby that can be serious.

Pregnant women with angina or an irregular heartbeat (arrhythmia) may need to continue using a calcium channel blocker to ensure that their heart remains healthy.

Use of a calcium channel blocker to treat Reynaud’s phenomenon, anal fissure, or to prevent cluster headaches can prevent the adverse effects on quality of life and wellbeing caused by these conditions.


What are the risks of using a calcium channel blocker in pregnancy?

There are no clear risks of taking a calcium channel blocker in pregnancy.

Nifedipine is commonly used in pregnancy and is unlikely to cause harm.

The other calcium channel blockers are less commonly used, and while not thought to cause problems, will only be recommended if the benefits of treating a potentially serious or lifestyle-impacting condition outweigh any possible risks.


Are there any alternatives to taking a calcium channel blocker in pregnancy?

Possibly. Other medicines can be used to treat high blood pressure or a heart problem in pregnancy but are not suitable for everyone. It is very important that these conditions are well-controlled, so staying on a calcium channel blocker might be the best option.

Women taking a calcium channel blocker for less serious conditions may be able to stop their medication during pregnancy.

Women who are taking a calcium channel blocker and planning a pregnancy, should speak to their doctor or specialist to make sure that it is ok to continue. No changes to medication should be made unless recommended by a doctor.

No treatment

What if I prefer not to take medicines in pregnancy?

It is important to take any medicines prescribed for high blood pressure or heart problems as these conditions can be serious for both mother and baby. Untreated high blood pressure can cause preterm birth, low infant birth weight, and illness in the mother and baby that can be serious.  Additionally, it is vital for the woman’s wellbeing that any condition that greatly impacts quality of life remains as well-controlled as possible. A doctor will only prescribe medicines when necessary and will be happy to discuss any concerns.

Will I or my baby need extra monitoring?

As part of routine antenatal care, most women will be offered a very detailed scan at around 20 weeks of pregnancy to check the baby’s development. No extra monitoring for major birth defects is required following use of a calcium channel blocker.

In general, women with high blood pressure and/or heart problems will be more closely monitored during pregnancy to make sure that they remain well throughout and that their baby is growing as expected.

Are there any risks to my baby if the father has taken a calcium channel blocker?

There is no evidence that a calcium channel blocker used by the father can harm the baby through effects on the sperm.

Who can I talk to if I have questions?

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

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.