Calcium channel blockers

Calcium channel blockers are a group of medicines that are used to treat a variety of conditions related to your heart.

What are calcium channel blockers?

Calcium channel blockers (CCBs) are a group of medicines commonly prescribed to treat conditions of the heart and blood vessels, such as high blood pressure (hypertension), chest pain (angina), and abnormal heart rhythms (eg, atrial fibrillation).

Calcium channel blockers may also be used to treat Raynaud’s syndrome, a condition that causes painful and cold fingers and toes due to narrowing of the blood vessels in your hands and feet. 

Calcium-channel blockers affect the way calcium passes into certain muscle cells causing these muscle cells to relax which in turn widens your blood vessels. This helps to:

  • lower blood pressure
  • reduce chest pain
  • treat abnormal heart rhythms
  • reduce your risk of stroke. 

Examples of calcium channel blockers

There are several different calcium channel blockers and your doctor will advise on which one is best for you. Calcium channel blockers include:

What to consider when taking calcium channel blockers

Taking other medicines and supplements

Calcium channel blockers can interact with some medicines, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting any new products.

You may need regular tests and checks

You are likely to have regular blood pressure and heart rate checks while taking calcium channel blockers. You're also likely to have regular blood tests to check your blood and kidney function.

Don’t stop taking your calcium channel blocker suddenly

If you think your medicine is not working for you, do not stop taking it suddenly as this can make you feel unwell and can cause chest pain. Talk to your doctor or nurse before stopping. It is usually best to stop taking your medicine slowly to avoid side effects.

What are the side effects of calcium channel blockers?

Like all medicines, calcium channel blockers can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine. For most people who take calcium channel blockers, serious side effects are rare.

The most common side effects are dizziness, flushing, headache and ankle swelling. If you get any side effects, talk to your doctor as soon as possible. 

Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.


  1. Calcium-channel blockers New Zealand Formulary
Credits: Health Navigator Pharmacists. Reviewed By: Maya Patel, MPharm PGDipClinPharm, Auckland Last reviewed: 22 Apr 2022