Verapamil is a calcium channel blocker used to treat irregular heart rhythms (arrhythmias) and high blood pressure.
If you have high blood pressure, verapamil helps to prevent future heart disease, heart attacks and stroke. You may also need to take it if you've had a heart attack.
Verapamil is also used to prevent chest pain caused by angina.
A specialist can also prescribe verapamil for cluster headaches. It can reduce the number of headaches you get.
Verapamil works by relaxing and widening blood vessels. This lowers blood pressure and helps to improve the blood and oxygen supply to your heart. It also relaxes the heart and slows down the heart rate, which helps to treat heart rhythm problems.
Verapamil is only available on prescription.
It comes as standard or slow-release tablets or as a liquid you swallow. It's also given as an injection, but this is usually only done in hospital.
Key facts
- Verapamil starts to work on the day you start taking it, but it may take 1 to 2 weeks to work fully.
- The most common side effect of verapamil is constipation.
- Do not eat grapefruit or drink grapefruit juice while you're taking verapamil. It can increase the amount of verapamil in your body and make side effects worse.
- If verapamil makes you feel dizzy, do not drive a car, ride a bike, or use tools or machinery until you feel better.
- It's important to keep taking verapamil. Stopping may cause your blood pressure to rise and this may increase your risk of a heart attack or stroke.