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  1. About nicorandil
  2. Key facts
  3. Who can and can't take nicorandil
  4. How and when to take it
  5. Side effects
  6. How to cope with side effects
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions

1. About nicorandil

Nicorandil is a medicine used to prevent and treat chest pain caused by angina.

Your doctor will usually prescribe nicorandil when other heart medicines have not worked or are not suitable for you.

This medicine is only available on prescription and comes as tablets.

2. Key facts

  • Nicorandil helps reduce your risk of having an angina attack by increasing the blood supply to your heart.
  • Taking nicorandil regularly can also reduce the risk of further heart conditions.
  • It's usual to take nicorandil twice a day.
  • Common side effects of nicorandil include headaches and feeling dizzy. These are usually mild and short-lived.
  • Nicorandil is also known by the brand name Ikorel.

3. Who can and can't take nicorandil

Nicorandil can be taken by adults aged 18 and over.

Nicorandil is not suitable for some people. Tell your doctor if you have:

  • had an allergic reaction to nicorandil or any other medicine in the past
  • low blood pressure (hypotension)
  • a problem with fluid build-up in the lungs (pulmonary oedema)
  • recently had a heart attack or been told you have heart failure
  • low blood potassium levels and are taking potassium supplements
  • kidney problems
  • a genetic condition called glucose-6-phosphate dehydrogenase deficiency
  • have a digestive condition that affects the large intestine (diverticular disease)
  • are taking regular non-steroidal anti-inflammatory medicines (NSAIDs), such as aspirin or steroid (corticosteroid) tablets

4. How and when to take it

It's usual to take nicorandil twice a day: once in the morning and once in the evening.

How much will I take?

Your dose will depend on how nicorandil works for you.

You'll usually start taking 1 10mg tablet twice a day. This may go up to 40mg if you need it.

If you often get headaches, you may be given a smaller starting dose of 5mg. This can be increased after about a week.

How to take it

You can take nicorandil tablets with or without food. Swallow the tablets whole with a drink of water.

The tablets have a score line across the middle. This helps you break them in half if you have difficulties swallowing tablets whole.

What if I forget to take it?

If you miss a dose of nicorandil, take the missed dose as soon as you remember. But if it's nearly time for your next dose, skip the missed dose.

Do not take a double to dose to make up for a missed dose.

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?

The amount of nicorandil that can lead to an overdose varies from person to person.

Urgent advice: Call your doctor or go to A&E straight away if you take too much nicorandil and:

  • feel dizzy or weak (signs of low blood pressure)
  • your heartbeat is fast or irregular

If you need to go to A&E, do not drive yourself.

Get someone else to drive you, or call for an ambulance.

Take the nicorandil packet or leaflet inside it, plus any remaining medicine, with you.

5. Side effects

Like all medicines, nicorandil can cause side effects, although not everyone gets them.

Common side effects

These common side effects may happen in more than 1 in 100 people. They're usually mild and go away by themselves:

Talk to your doctor or pharmacist if these side effects bother you or do not go away:

  • headaches
  • feeling dizzy or weak
  • feeling or being sick (nausea and vomiting)
  • flushing (also known as blushing)

Serious side effects

Serious side effects are rare and happen in less than 1 in 10,000 people.

Tell your doctor straight away if you get :

  • red, itchy or watery eyes – these can be signs of conjunctivitis or a corneal ulcer
  • painful sores (ulcers) on the eyes, skin or the lining of the mouth
  • stomach pain, feeling or being sick, loss of appetite, blood in your poo – these are signs of stomach ulcers

These rare side effects can happen at any time. If you notice ulcers on any part of your body, you'll need to stop taking nicorandil straight away.

Serious allergic reaction

In rare cases, nicorandil may cause a serious allergic reaction (anaphylaxis).

Immediate action required: Call 999 or go to A&E if:
  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you get tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of nicorandil.

For a full list, see the leaflet inside your medicines packet.


You can report any suspected side effect to the UK safety scheme.

6. How to cope with side effects

What to do about:

  • headaches - make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller. Headaches usually go away after the first week of taking nicorandil. Talk to your doctor if the headaches last longer than a week or are severe.
  • feeling dizzy or weak - if nicorandil makes you feel dizzy or weak, stop what you're doing and sit or lie down until you feel better. Do not drive or use tools or machinery if you're feeling tired. Do not drink alcohol, as it'll make you feel worse. Speak to your doctor if you still feel dizzy after a week.
  • feeling or being sick- stick to simple meals and do not eat rich or spicy food. It might help to take your nicorandil after you have eaten. If you're being sick, try small, frequent sips of water to avoid dehydration. Talk to your doctor if these symptoms last more than a few days or you notice blood in your vomit.
  • flushing (also known as blushing) - 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 redness should go away after a few days. If it does not stop or is bothering you, talk to your pharmacist or doctor.

7. Pregnancy and breastfeeding

Nicorandil is not usually recommended in pregnancy or breastfeeding. There's not enough information available to say whether it's safe or not.

If you're trying to get pregnant, are already pregnant or breastfeeding, talk to your doctor about the benefits and possible harms of taking nicorandil.

Your doctor will be able to recommend the best treatment for you and your baby.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

8. Cautions with other medicines

There are some medicines that may interfere with the way nicorandil works.

Some medicines can lower your blood pressure too much when they're taken with nicorandil. This can make you feel dizzy or faint.

Tell your doctor if you're taking:

  • medicines used to treat high blood pressure
  • antidepressants
  • muscle relaxants, such as baclofen
  • riociguat, a medicine used for pulmonary hypertension
  • potassium supplements or medicines that increase potassium levels – these include ACE inhibitors, such as lisinopril and ramipril, and angiotensin receptor blockers (ARB), such as valsartan, losartan and candersartan
  • medicines for Parkinson's disease, like co-careldopa and levodopa
  • medicines used to treat erectile dysfunction, like sildenafil or tadalafil, or vardenafil or dapoxetine, used for premature ejaculation
  • steroids like prednisolone – these can increase the risk of stomach ulcers

Taking nicorandil with painkillers

It's safe to take nicorandil with paracetamol. But avoid painkillers known as NSAIDs like ibuprofen and high-dose aspirin. This is because they can increase the risk of stomach ulcers.

Mixing nicorandil with herbal remedies and supplements

There are no known problems with taking herbal remedies and supplements alongside nicorandil.


For safety, tell your doctor or pharmacist if you're taking any other medicines, including herbal medicines, vitamins or supplements.

9. Common questions

How does it work?

Nicorandil is a type of medicine called a potassium-channel activator.

It works by relaxing and widening your blood vessels, which increases the supply of blood and oxygen to your heart.

This helps reduce the chest pain angina causes.

How long does it take to work?

Nicorandil starts to work after about 1 hour, but it usually takes about 4 to 5 days for it to fully take effect.

How long will I take it for?

Usually, treatment with nicorandil is long term, even for the rest of your life.

Is it safe to take for a long time?

Nicorandil is generally safe to take for a long time.

In fact, it works best when you take it for a long time.

What will happen if I stop taking it?

Talk to your doctor if you want to stop taking nicorandil.

Stopping nicorandil can make your angina pain come back.

If you're bothered by side effects, your doctor may be able to prescribe a different medicine for your angina.

If you stop taking nicorandil, it'll take around 2 days for it to be completely out of your body.

How does it compare with other heart medicines?

Nicorandil is not usually the first-choice treatment for angina.

The usual medicines used to prevent angina attacks are:

  • beta blockers (like bisoprolol) – these make the heart beat slower and with less force
  • calcium channel blockers (like amlodipine) – these relax the arteries, increasing blood supply to the heart muscle

If these medicines do not work for you or give you side effects, you may be given another medicine, such as nicorandil, ivabradine or ranolazine.

These medicines are also known as second-line treatments for angina.

Nicorandil, ivabradine and ranolazine work in different ways, so it's difficult to say whether one is better than the other.

Some people may need to take a combination of medicines to control their angina symptoms.

Will I need to stop taking it before surgery?

You can take nicorandil as normal before and after surgery.

Will it affect my contraception?

Nicorandil does not affect any type of contraception, including the combined pill and emergency contraception.

Will it affect my fertility?

There's no firm evidence to suggest that taking nicorandil will reduce fertility in either men or women.

If you're trying for a baby or having problems getting pregnant while on nicorandil, speak to your doctor.

Can I drink alcohol with it?

Drinking alcohol can increase the blood pressure-lowering effect of nicorandil. This can make you feel dizzy or lightheaded.

During the first few days of taking nicorandil or after an increase in your dose, avoid drinking alcohol until you see how the medicine affects you.

If you find nicorandil makes you feel dizzy, it's best to stop drinking alcohol.

Is there any food or drink I need to avoid?

You can eat and drink normally while taking nicorandil.

Do not use salt substitutes such as Lo-Salt. This is because they're high in potassium.

When mixed with nicorandil, they make the level of potassium in your blood too high.

Will it affect my sex life?

Nicorandil should not affect your sex life.

But medicines used to treat erectile dysfunction, such as sildenafil or tadalafil, or vardenafil or dapoxetine (used to treat premature ejaculation), are not recommended while taking nicorandil.

Taking them together can lead to a serious drop in your blood pressure.

Do I need to avoid playing sports?

You do not need to stop playing sports if you take nicorandil.

But do not push yourself too much. It's best to build up your activity gradually and take regular breaks.

Regular exercise is good for you because it lowers blood pressure by keeping your heart and blood vessels in good condition.

Can I drive or ride a bike?

Nicorandil can make some people feel dizzy, especially when you first start taking it or after taking a bigger dose.

If this happens to you, do not drive a car, ride a bike, or use tools or machinery until you feel better.

Can lifestyle changes help?

You can boost the health of your heart by making some key lifestyle changes:

Page last reviewed: 28 February 2019
Next review due: 28 February 2022