Verapamil

Sounds like 'ver-AP-a-mil'

Easy-to-read medicine information about verapamil – what it is, how to take verapamil safely and possible side effects. Verapamil is commonly called Isoptin.

Type of medicine Also called
  • Antihypertensive (to lower blood pressure)
  • Used to prevent chest pain (angina)
  • Belongs to a group of medicines called calcium channel blockers
  • Isoptin®
  • Isoptin SR®
  • Verpamil SR®

What is verapamil?

Verapamil is used to treat high blood pressure (hypertension) and to prevent chest pain (angina). It may help to increase your ability to exercise and decrease how often you get chest pain. Verapamil may also be used to control your heart rate if you have a fast or irregular heartbeat (such as atrial fibrillation). It works by relaxing blood vessels which helps to lower blood pressure. Verapamil belongs to a group of medicines called calcium channel blockers. In New Zealand, verapamil is available as immediate-release tablets and slow release tablets.

Dose

  • The dose of verapamil will be different for different people. Your doctor will tell you which dose is right for you.
  • Verapamil is available in 2 forms – as immediate release tablets and slow release tablets. Check with your pharmacist which form you are taking.
  • Always take your verapamil exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much verapamil to take, how often to take it, and any special instructions.

How to take verapamil

Verapamil immediate release and slow release tablets are available in different strengths. If your tablets look different to your last supply speak with your doctor or pharmacist for advice.

 Formulation  How to take it

Immediate release tablets

(40 mg and 80 mg)
  • These are usually taken two or three times daily.
  • Try to space your doses evenly throughout the day.
  • You can take verapamil with or without food.
  • Take your tablets with a glass of water.
  • Swallow your tablets whole. If you have trouble swallowing them, they can be crushed. Ask your pharmacist for advice.

Slow release tablets

(120 mg and 240 mg)
  • These are usually taken once or two times daily.
  • Take your doses at the same times each day.
  • You can take verapamil with or without food.
  • Swallow the slow release tablets whole, with a glass of water. Do not crush or chew them.

Limit or avoid drinking alcohol while taking verapamil. Alcohol may increase your chance of side-effects, such as feeling dizzy or light-headed.
Missed dose: If you forget your dose, take it as soon as you remember. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
Keep taking verapamil regularly. Do not stop taking verapamil suddenly; speak to your doctor or nurse before stopping.

Precautions – before taking verapamil

  • Do you have problems with your liver?
  • Do you have heart problems such as heart failure, a slow heart rate, low blood pressure or have you had a heart attack recently?
  • Are you pregnant, trying for a baby or breastfeeding?
  • Are you taking any other medicines? This includes any medicines you buy without a prescription, such as herbal and complementary medicines.

If so, it’s important that you tell your doctor or pharmacist before you start verapamil. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Side effects

Like all medicines, verapamil can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Constipation
  • Constipation is quite common
  • Eat more fruit, vegetables, brown bread, bran-based breakfast cereals and drink plenty of water to prevent constipation.
  • If you have problems with constipation before starting verapamil, tell your doctor. You may be prescribed a laxative, which you need to take on a regular basis
  • Headache
  • Nausea (feeling sick)
  • Tiredness
  • This is quite common when you first start taking verapamil and usually goes away with time
  • Tell your doctor if troublesome 
  • Dizziness
  • Feeling light-headed
  • Feeling faint when you stand up
  • This is common when you first start taking verapamil and usually goes away with time
  • Be careful when getting up from either lying down or sitting to avoid falls
  • Avoid drinking alcohol
  • Tell your doctor if troublesome 
  • Changes in your heartbeat (either too slow, too fast or irregular)
  • Chest tightness
  • Wheezing or trouble breathing
  • Swelling of the ankles or feet
  • Tell your doctor immediately or ring HealthLine 0800 611 116

Interactions

Verapamil may interact with a few medications and herbal supplements, so check with your doctor or pharmacist before starting verapamil or before starting any new medicines, including those you may buy over the counter.

Learn more

The following links have more information on verapamil.

Medsafe Consumer Information Sheet:
Isoptin
Isoptin SR
Verpamil SR

New Zealand Formulary Patient Information: verapamil

References

  1. Verapamil hydrochloride New Zealand Formulary
  2. Medical management of stable angina pectoris BPAC, 2011
  3. An update on managing patients with atrial fibrillation BPAC, 2017
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 15 Nov 2018