Calcium channel blockers

Calcium channel blockers can help treat high blood pressure, abnormal heart rhythms and angina. Read about the types of calcium channel blockers, how they work and possible side effects.

Types of calcium channel blockers

amlodipine, also called Vasorex
diltiazem, also called Diltiazem CD Clinect, Cardizem CD
felodipine, also called Felo ER, Plendil ER
nifedipine, also called Nyefax Retard
verapamil, also called Isoptin, Isoptin SR

How do calcium channel blockers work?

Calcium channel blockers reduce the amount of calcium in the cells of your heart and blood vessel walls. This relaxes and widens your blood vessels.

Diltiazem and verapamil also have a direct effect on your heart’s electric system, which can slow your heart rate.

Calcium channel blockers are used to help:

lower blood pressure
prevent angina
management of atrial fibrillation (diltiazem and verapamil only).

Calcium channel blocker side effects

You may experience some unwanted side effects when taking calcium channel blockers.

These can include:

swelling of the ankles or feet
headaches
dizziness
flushing (feeling hot or going red in the face)
light-headedness (blood pressure may be too low)
nausea (feeling sick) or vomiting (being sick)
constipation (your poo is hard and difficult to pass)
palpitations (feeling that your heart is pounding, fluttering or skipping beats)
slower heart rate.

Call 111 if you have any of these:

severe chest pain
severe headache
sudden shortness of breath (your breathing is so difficult that you feel unsafe)
swelling of your mouth, lips or tongue, as this could be an allergic reaction.

Talk to your doctor if the side effects are worrying you. Don’t stop taking your medication without talking to your doctor first. The benefits usually outweigh the side effects.

What checks do I need?

You are likely to have regular blood pressure and heart rate checks while taking calcium channel blockers.

You may need regular blood tests.

What if I miss a dose of calcium channel blockers?

It’s important to take your medication daily and not to skip a dose.

If you forget to take a dose, take it immediately, then continue as normal the following day. However, if it’s almost time for the next dose, skip the missed dose and continue as normal.

Do NOT take a double dose.

What else do I need to know?

Tell your doctor if you’re taking any:

vitamins
supplements
natural medicines
medicines bought from a pharmacy without a prescription
alternative therapies.

These can sometimes make your heart medications less effective.

If you are taking certain calcium channel blockers you should not eat grapefruit or drink grapefruit juice, as they can interfere with how your body breaks down the drug and increase the risk of side effects. Talk to your doctor or pharmacist and ask if this applies to your medication.

Talk to your doctor if you: