Sounds like 'is-RAD-i-peen'

Easy-to-read medicine information about isradipine – what is it, how to take isradipine safely and possible side effects.

Type of medicine Also called
  • Antihypertensive (to lower blood pressure)
  • Belongs to a group of medicines called calcium channel blockers
  • Dynacirc SRO®

What is isradipine?

Isradipine is used to treat high blood pressure (hypertension). It works by relaxing your blood vessels so blood can flow more easily, and in this way lowers your blood pressure. Isradipine belongs to a group of medicines called calcium channel blockers. In New Zealand isradipine is available in different strengths of capsules (2.5 mg and 5 mg). 


  • The usual dose of isradipine is 2.5 milligrams or 5 milligrams once daily. 
  • Always take your isradipine exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much isradipine to take, how often to take it, and any special instructions.

How to take isradipine

  • Take isradipine once a day. Try to take your doses at the same time each day.
  • Swallow your capsule with a glass of water.
  • You can take isradipine with or without food.
  • Limit or avoid drinking alcohol while you are taking isradipine. It may increase your chance of side effects such as feeling dizzy.
  • If you forget your dose, take it as soon as you remember that day. 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.
  • Do not stop taking isradipine suddenly; speak to your doctor or nurse before stopping.
  • Isradipine capsules are available in different strengths. If your capsules look different to your last supply speak with your doctor or pharmacist for advice.

Precautions – before taking isradipine

  • Do you have heart problems such as heart failure 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 isradipine. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Possible side effects

Like all medicines, isradipine 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?
  • Tiredness
  • Headache
  • Feeling flushed or hot
  • These are quite common when you first start taking isradipine and usually go away after the first few days
  • Tell your doctor if troublesome
  • Dizziness
  • Feeling lightheaded
  • Feeling faint when you stand up
  • Be careful when getting up from either lying down or sitting to avoid falls. These effects put you at risk of falls and injuries, especially if you are elderly
  • Be careful when driving or using tools until you know how this medicine affects you
  • Avoid drinking alcohol
  • Swollen ankles or feet
  • Tell your doctor
  • Changes in your heartbeat (either too fast or irregular)
  • Tell your doctor
  • Worsening chest pain, shortness of breath, pain in the chest, rash
  • Tell your doctor immediately or ring HealthLine 0800 611 116


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

Learn more

The following links have more information on isradipine.

Medsafe Consumer Information Sheet: Dynacirc SRO

Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 28 Nov 2018