Calcium-channel blockers (CCBs) are a type of medicine often used to treat high blood pressure.
They work mainly by allowing the blood vessels to relax and widen so the blood has more space to flow through. Most have names that end in ‘pine’ (pronounced, peen), for example, amlodipine, felodipine and nifedipine, as well as others including diltiazem and verapamil.
How do calcium-channel blockers work?
Calcium-channel blockers work by stopping the calcium in your blood from entering the muscle cells in your blood vessel walls. When calcium enters these cells, the muscles contract and tighten up, making your blood vessels narrower. This means your blood has less space to flow through, raising your blood pressure.
Calcium-channel blockers allow your blood vessels to relax and open up, making it easier for blood to flow through.
This short video explains how calcium-channel blockers work.
There are different types of calcium-channel blockers which work in different ways. Some work more on the heart than on the blood vessels so can be used for heart conditions.
Who can take calcium-channel blockers?
If you have high blood pressure, your doctor or nurse might suggest you take medicines to lower it. It can take some trial and error to find the right one or the right combination, and calcium-channel blockers are often one of the first ones you will try, either on their own or alongside another one.
They’re often suitable if you’re over 55 or of African or Caribbean descent, but can still be an option if that doesn’t apply to you.
Calcium-channel blockers can also be suitable if you’re pregnant or breastfeeding. They can also be a good option if your blood pressure is very high or if you have certain heart problems, for example angina (chest pain), an irregular heartbeat (including atrial fibrillation) or a fast heart rate. You will need to have regular check-ups to make sure they’re safe for you.
When are calcium-channel blockers not suitable?
Some types of calcium blockers might not be suitable if you have certain health problems, or you might need more careful monitoring. For example, if you have heart failure or if you’re taking other medications which could interfere with them. Your doctor will consider your overall health and any treatments you’re having before giving you any new medicines.
Do calcium-channel blockers have side-effects?
All medicines can have side effects, including blood pressure medicines. It’s likely you won’t have any side effects at all with calcium-channel blockers, or you might have some that are minor and don’t cause you too many problems.
If you have side effects which don’t improve and are affecting your day-to-day life, speak to your GP because you should be able to try a lower dose or a different medicine.
Possible side effects of calcium-channel blockers include:
- a flushed face
- swollen ankles
- palpitations (where you are aware of your heart beat)
- ankle or foot pain
- skin rashes
- dizziness or tiredness
- a sudden drop in blood pressure when you go from lying or sitting down to standing up (postural hypotension)
The leaflet that comes with your medicine will have a full list of possible side effects.
Taking calcium-channel blockers
You take calcium-channel blockers as a tablet, usually once a day. They can also be part of a combined tablet – where more than one medicine is combined in one tablet – for example with ACE inhibitors or angiotensin receptor blockers.
Avoid drinking grapefruit juice if you’re taking calcium-channel blockers, with the exception of amlodipine and diltiazem. Grapefruit allows more of the medicine to enter your blood stream, so your blood pressure can drop very suddenly.
Check with your doctor or pharmacist before taking any other medicines at the same time as calcium-channel blockers, as they can interact, including medicines you buy over the counter such as painkillers and anti-inflammatories.
If you start taking high blood pressure medicines, it’s likely you will need to keep taking them for the long term. If your blood pressure stays under control for several years, you might be able to take a lower dose or stop taking them altogether.
It’s important that you don’t simply stop taking calcium-channel blockers because your blood pressure will quickly rise again, and if you have angina, you could have chest pain. Always let your doctor, nurse or pharmacist know if you’re struggling because there could be other options you can try.
Calcium-channel blockers (CCBs) information sheet