Verapamil
Sounds like 'ver-ap-ah-mil'
Key points about verapamil
- Verapamil is used to treat high blood pressure, irregular heart beat and to prevent chest pain (angina)
- Verapamil is also called Isoptin®.
- Find out how to take it safely and possible side effects.

Verapamil belongs to a group of medicines called calcium channel blockers or calcium antagonists. It doesn’t affect the amount of calcium in your blood or bones.
Verapamil is used to treat high blood pressure (hypertension) and to prevent chest pain (angina). It may help you exercise more 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 with atrial fibrillation).
It works by relaxing blood vessels which helps to lower your blood pressure.
In Aotearoa New Zealand, verapamil is known as Isoptin® or Isoptin SR®.
It’s available as immediate-release tablets (40 mg and 80 mg) and slow release tablets (120 mg and 240 mg). It can also be given as an injection, but this is usually only done in hospital.
- The dose of verapamil will be different for different people. Your healthcare provider 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're taking.
- Always take your verapamil exactly as your healthcare provider 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.
Verapamil immediate release and slow release tablets are available in different strengths. If your tablets look different to your last supply ask your pharmacist about it.
Formulation | How to take it |
Immediate release tablets (40 mg and 80 mg) |
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Slow release tablets (120 mg and 240 mg) |
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Missed dose: If you forget your dose, take it as soon as you remember. But if it’s nearly time for your next dose, just take the next dose at the usual time. Don’t take double the dose.
Here are some things to know when you're taking verapamil. Other things may be important as well, so ask your healthcare provider what you should know about.
- Other medicines:
- Verapamil interacts with some medicines (eg, atorvastatin, colchicine), herbal supplements (eg, St John's Wort) and rongoā Māori, so check with your healthcare provider before starting verapamil and before starting any new products.
- Verapamil can interact with anti-inflammatories you can buy over the counter, such as diclofenac (eg, Voltaren®), ibuprofen (eg, Nurofen®), or aspirin (eg, Disprin®, in doses used for pain relief). Anti-inflammatories can also be found in some cold and flu medicines (eg, Nurofen Cold and Flu®).
- Alcohol: Verapamil can make you feel tired or dizzy. Limit or avoid drinking alcohol while you're taking verapamil. Alcohol may increase these side-effects.
- Keep taking verapamil regularly: Don’t stop taking verapamil suddenly; talk to your healthcare provider before stopping.
- Grapefruit, grapefruit juice or sour/Seville oranges: Avoid grapefruit, grapefruit juice or foods containing grapefruit while taking verapamil. It can increase the amount of verapamil in your body. Read more about grapefruit and medicines.
- Pregnancy or breastfeeding: Talk to your healthcare provider if you're pregnant, planning a pregnancy or want to breastfeed.
- Monitoring: You may have blood tests to check how well your liver is working.
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.
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Read more about medicines and side effects and reporting a reaction you think might be a side effect.
The following links have more information on verapamil.
Verapamil(external link) New Zealand Formulary Patient Information
Isoptin® and Isoptin SR®(external link) Medsafe Consumer Information, NZ
Brochures
Medicines and side effects(external link) Healthify He Puna Waiora, NZ, 2024
5 questions to ask about your medications(external link) Health Quality and Safety Commission, NZ, 2019 English(external link), te reo Māori(external link)
References
- Verapamil hydrochloride(external link) New Zealand Formulary
- Isoptin®(external link) Medsafe datasheet, NZ
- Hypertension in adults – the silent killer(external link) BPAC, NZ, 2023
- An update on managing patients with atrial fibrillation(external link) BPAC, NZ, 2017
- Medical management of stable angina pectoris(external link) BPAC, NZ< 2011
Brochures
Medicines and side effects
Healthify He Puna Waiora, NZ, 2024
Health Quality and Safety Commission, NZ, 2019 English, te reo Māori
Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.
Reviewed by: Stephanie Yee, Pharmacist, Auckland
Last reviewed: