Verapamil
About verapamil
Verapamil is used to prevent chest pain caused by angina as well as irregular heart rhythms (arrhythmias).
It's also used to treat high blood pressure (hypertension).
If you have high blood pressure, taking verapamil helps to prevent:
A specialist can also prescribe verapamil for cluster headaches. It can reduce the number of headaches you get.
Verapamil is only available on prescription.
It comes as 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 lowers your blood pressure and makes it easier for your heart to pump blood around your body.
- Verapamil starts to work on the day you start taking it, but it may be 1 or 2 weeks before it reaches its full effect.
- The most common side effect of verapamil is constipation.
- Do not eat grapefruit or drink grapefruit juice while you’re taking verapamil. It can make side effects worse.
- 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.
Who can and cannot take verapamil
Most adults can take verapamil. It can also be given to children aged 1 year and over.
Verapamil is not suitable for some people. To make sure verapamil is safe for you, tell your doctor if you:
- have ever had an allergic reaction to verapamil or any other medicine
- have liver problems
- have low blood pressure (hypotension)
- have any other heart problems, including heart failure, or a very slow or irregular heart rate
- have a heart condition called Wolff-Parkinson-White syndrome
- are trying to get pregnant, are already pregnant or breastfeeding
How and when to take verapamil
Take verapamil exactly as your doctor has told you and follow the instructions that come with your medicine. If you're not sure, ask a pharmacist or your doctor.
Verapamil comes as standard tablets, slow-release (long-acting) tablets, and a liquid (oral solution).
Slow-release tablets release the medicine gradually into your body. This means you do not need to take them as often.
Dosage
The dose of verapamil depends on why you're taking it.
If you have liver disease, your doctor may prescribe you a low dose and will monitor you more closely.
If a doctor has prescribed verapamil for your child, the dose will usually be lower than adults. It will depend on how old your child is. Children will usually be given standard tablets or liquid.
Dosage for high blood pressure
Standard tablets or liquid – you'll usually start on a dose of 120mg, taken twice a day. Your doctor may increase your dose to a maximum of 480mg a day, split into divided doses.
Slow-release tablets – you'll usually start on a dose of 240mg, taken once a day. Your doctor may increase it to 480mg a day. If your dose is higher than 240mg daily, it can be split into 2 doses and taken morning and evening.
Liquid verapamil contains 40mg in each 5ml spoonful.
Dosage for angina
Standard tablets or liquid – the usual dose is 80mg or 120mg, taken 3 times a day, although some people may find that taking verapamil twice a day is enough to control their symptoms.
Long-acting tablets – the usual dose is 240mg, taken twice a day. Your doctor might reduce this dose to 240mg, taken once a day.
Dosage for irregular heart rhythm
Standard tablets or liquid – the usual dose is between 40mg and 120mg, taken 3 times a day.
Dosage after a heart attack
Slow-release tablets – the usual dose is 360mg a day, split into 2 or 3 doses throughout the day. This can be taken as 240mg in the morning and 120mg in the evening, or as 120mg taken 3 times a day.
You'll usually wait at least 1 week after a heart attack before starting verapamil.
Will my dose go up or down?
If the dose you start on does not work well enough (your blood pressure does not lower enough, or your angina is not controlled), then your doctor will gradually increase your dose.
Your doctor may also lower your dose if your blood pressure is controlled or the side effects bother you.
How to take verapamil
Swallow your tablets whole with a drink of water. Do not chew or crush them, as it's important that they go into your stomach before they dissolve.
You can take verapamil at any time of day. It may help you to remember if it's the same time each day.
If you're taking verapamil as a liquid, it will come with a plastic syringe or spoon to help you take the right amount. If you do not get one, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not give you the right amount.
You can take verapamil with or without food.
It's important not to eat grapefruit or drink grapefruit juice while you're taking this medicine. Grapefruit can increase the amount of verapamil in your body and make side effects worse.
What if I forget to take it?
If you forget to take your medicine, take it as soon as you remember unless it's nearly time for your next dose. In this case, leave out the missed dose and take the next one at the usual time.
Do not take 2 doses at the same time to make up for a missed dose. Never take an extra dose to make up for a forgotten one.
If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.
What if I take too much?
Taking too much verapamil can cause your blood pressure to go too low. It can also make you feel faint, dizzy or sleepy because it can cause your heart to beat irregularly.
Contact 111 for advice if:
- you take too much verapamil
Call 111 or go to 111.nhs.uk
If you need advice for a child under the age of 5 years, call 111.
If you need to go to the hospital, do not drive yourself. Get someone else to drive you or call for an ambulance.
Take your verapamil packet or the leaflet inside it plus any remaining medicine with you.
Side effects
Like all medicines, verapamil can cause side effects in some people, but many people have no side effects or only minor ones.
Side effects often get better as your body gets used to the medicine.
Common side effects
Common side effects happen in more than 1 in 100 people. They are usually mild and do not last long.
Talk to your doctor or pharmacist if these side effects bother you or do not go away:
- constipation
- feeling or being sick (nausea or vomiting)
- flushing of the face and neck
- headaches
- feeling dizzy or tired
- swollen hands, ankles or feet
Serious side effects
Serious side effects are rare and happen in less than 1 in 10,000 people.
Stop taking verapamil and tell your doctor straight away if:
- the whites of your eyes or your skin turn yellow, although this may be less obvious on brown or black skin, or you have dark pee – these can be signs of liver problems
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to verapamil.
These are not all the side effects of verapamil. For a full list see the leaflet inside your medicines packet.
How to cope with side effects of verapamil
What to do about:
- constipation – eat more high-fibre foods such as fresh fruit, vegetables and cereals, and drink plenty of water. If you can, it may also help to increase your level of exercise. If this does not help, talk to your pharmacist or doctor about treatments for constipation.
- feeling or being sick – stick to simple meals and do not eat rich or spicy food. It might help to take your verapamil after a meal or snack. If you are being sick, try to take small, frequent sips of water to avoid dehydration.
- flushing – try cutting down on coffee, tea and alcohol. It might help to keep the room cool and use a fan. You could also spray your face with cool water or sip cold or iced drinks. The flushing should go away after a few days. If it does not go away or it's causing you problems, contact your doctor.
- headaches – make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Paracetamol is safe to take with verapamil. Headaches should usually go away after the first week of taking verapamil. Talk to your doctor if they last longer than a week or are severe.
- feeling dizzy or tired – if verapamil makes you feel dizzy, stop what you're doing and sit or lie down until you feel better. If it makes you feel tired make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Do not drive, ride a bike or operate tools or machinery until you feel OK.
- swollen hands, ankles or feet – raise your legs or elevate your arms on a cushion when you're sitting down. This will get better after a few days as your body gets used to the medicine. If it does not, or it gets worse, speak to your doctor.
Pregnancy and breastfeeding
Verapamil and pregnancy
Verapamil can be taken during pregnancy, although it is not commonly used.
If you need to take verapamil to treat high blood pressure you will usually be switched to a different medicine.
If you're taking verapamil for angina or heart rhythm problems then you will be reviewed in a maternity clinic with a pregnancy specialist (obstetrician) and a heart specialist (cardiologist). Keep taking verapamil until you have been reviewed.
Verapamil and breastfeeding
If your doctor, health visitor or midwife says your baby is healthy, it is OK to breastfeed while taking verapamil.
Verapamil passes into breast milk in small amounts, and it's unlikely to cause any side effects in your baby.
It's important to keep taking verapamil to keep you well. Breastfeeding will also benefit both you and your baby.
If you notice that your baby is not feeding as well as usual, or seems unusually sleepy, or if you have any other concerns about your baby, talk to your health visitor or midwife as soon as possible.
Read about high blood pressure in pregnancy.
For more information about how verapamil and other calcium channel blockers can affect you in pregnancy, read this leaflet on the Best Use of Medicines in Pregnancy (BUMPs) website.
Cautions with other medicines
Some medicines can affect the way verapamil works.
Taking verapamil with other medicines that lower your blood pressure can sometimes lower it too much. This may make you feel dizzy or faint. If this happens to you, tell your doctor, as they may need to change your dose.
Tell your doctor if you are taking any of these medicines before starting verapamil:
- antibiotics, such as clarithromycin, erythromycin or rifampicin
- antifungal medicines, such as itraconazole or ketoconazole
- ivabradine, a medicine for angina and heart failure
- darunavir or ritonavir, medicines that treat HIV or hepatitis C
- epilepsy medicines like carbamazepine or phenytoin
- medicines that suppress your immune system, such as cyclosporin or tacrolimus
- more than 20mg a day of simvastatin (a medicine used to lower cholesterol)
Mixing verapamil with herbal remedies and supplements
St John's wort (a herbal remedy for depression) can affect the way verapamil works.
Talk to a pharmacist or doctor before taking St John's wort.