Dipyridamole: a blood thinning medicine to prevent blood clots - NHS

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  1. About dipyridamole
  2. Key facts
  3. Who can and can't take dipyridamole
  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 dipyridamole

Dipyridamole is an antiplatelet medicine, or blood thinner. It makes your blood flow through your veins more easily. This means your blood will be less likely to make a dangerous blood clot.

Taking dipyridamole helps to prevent blood clots if you have an increased risk of having them. Your risk is higher if you have or have had:

Dipyridamole is only available on prescription.

It comes as tablets and slow-release (called "modified-release") capsules. It is also available as a liquid if you find it difficult to swallow tablets or capsules.

2. Key facts

  • The usual dose for dipyridamole is 200mg twice a day for slow-release capsules or 300mg to 600mg taken 3 or 4 times a day for tablets or liquid.
  • Your doctor may prescribe dipyridamole alone or with .
  • The main side effects of dipyridamole are feeling sick (nausea), diarrhoea and being sick (vomiting), headaches, feeling dizzy, or feeling hot and flushed.
  • You can drink alcohol with dipyridamole. However, do not drink too much while taking this medicine. It can make you dizzy or lightheaded.
  • Dipyridamole is also called by the brand names Attia, Ofcram, Persantin, Persantin Retard and Trolactin. Some products may contain a combination of dipyridamole and (with the brand names Atransipar and Molita).

3. Who can and can't take dipyridamole

Dipyridamole can be taken by adults to prevent strokes and after heart valve replacement surgery.

It is sometimes prescribed for children to treat a rare illness called Kawasaki disease or prevent blood clots after heart surgery.

Dipyridamole isn't suitable for some people. To make sure this medicine is safe for you, tell your doctor if you:

4. How and when to take it

How much dipyridamole you take depends on what form you have been prescribed.

  • Slow-release (modified-release) capsules: these release the medicine slowly in your body over a number of hours. Take 1 capsule twice a day - usually 1 in the morning and 1 in the evening. Take your capsules with or shortly after a meal. Swallow the capsule whole. Do not crush or chew it. Capsules are not prescribed for children.
  • Tablets or liquid: your doctor will tell you whether to take your dose 3 or 4 times a day. Take it before meals at the same time each day. Swallow the tablet whole with a glass of water. Dipyridamole liquid comes with a syringe or a spoon to help you take the right amount. If you don't have a syringe or spoon, ask your pharmacist for one.

How much should I take?

The usual dose for slow-release capsules is 200mg twice a day.

The usual dose for tablets and liquid is 300mg to 600mg taken 3 or 4 times a day. Follow your doctor's instructions.

If the doctor prescribes it for your child, they usually need to take it 2 or 3 times a day. The doctor will use your child's weight to work out the right dose.

What if I forget to take it?

If you forget to take dipyridamole, take it as soon as you remember. If it's nearly time for your next dose, skip the missed dose.

Don't take a double dose to make up for a forgotten dose.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to remember to take your medicines.

What if I take too much?

Accidentally taking 1 or 2 extra doses is unlikely to harm you. However, the amount of dipyridamole that can lead to overdose is different from person to person.

Contact your doctor straight away if you've taken some extra medicine and you get side effects such as:

  • a faster heart rate or pain in your chest - these can be signs of a heart problem
  • feeling dizzy or lightheaded, especially when you stand up or sit up quickly
  • shortness of breath, wheezing and tightening of the chest

5. Side effects

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

Common side effects

These common side effects happen in more than 1 in 100 people. Talk to your doctor or pharmacist if these side effects bother you or don't go away:

  • feeling sick (nausea)
  • diarrhoea and being sick (vomiting)
  • headaches
  • feeling dizzy
  • feeling hot and flushed

Serious side effects

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

Call a doctor straight away if:

  • you have chest pain, or a fast or uneven heartbeat
  • your skin or the whites of your eyes turn yellow - these are signs of a liver problem

Serious allergic reaction

In rare cases, dipyridamole can cause a serious allergic reaction.

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


You can report any suspected side effect to the .

6. How to cope with side effects

What to do about:

  • feeling sick (nausea) - try taking your tablets with or after a meal or snack. It may also help if you don't eat rich or spicy food.
  • diarrhoea and being sick (vomiting) - drink plenty of water in small, frequent sips. Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee. Don't take any other medicines to treat diarrhoea or vomiting without speaking to a pharmacist or doctor.
  • headaches - make sure you rest and drink plenty of fluids. Don't drink too much alcohol. Ask your pharmacist to recommend a painkiller. Talk to your doctor if the headaches are severe or last longer than a week.
  • feeling dizzy - if dipyridamole makes you feel dizzy when you stand up, try getting up very slowly or stay sitting down until you feel better. If you begin to feel dizzy, lie down so that you don't faint, then sit until you feel better. Don't drive or use tools or machines if you feel dizzy or a bit shaky.
  • feeling hot and flushed - 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 doesn't, or if it's causing you problems, contact your doctor.

7. Pregnancy and breastfeeding

Dipyridamole isn't normally recommended in pregnancy or when breastfeeding. However, your doctor may prescribe it if they think the benefits of the medicine outweigh the risks.

If you're planning a pregnancy or you are already pregnant, talk to your doctor about the benefits and possible harms of taking dipyridamole. These will depend on how many weeks pregnant you are and the reason you need to take it. There may be other treatments that are safer for you.

Dipyridamole and breastfeeding

There is not a lot of information about the safety of dipyridamole if you're breastfeeding. It's not known how much dipyridamole may get into your breast milk.

Talk to your doctor to discuss your choices if you want to breastfeed.

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

  • trying to get pregnant
  • pregnant
  • breastfeeding

8. Cautions with other medicines

Some medicines interfere with the way dipyridamole works.

Tell your doctor if you're taking these medicines before you start taking dipyridamole:

  • medicines to thin blood or prevent blood clots, such as , , or
  • medicines for high blood pressure, such as , or
  • indigestion medicines, such as ranitidine, proton pump inhibitors like , or antacids that contain magnesium or aluminium
  • digoxin for heart problems
  • medicines used to treat myasthenia gravis

Taking dipyridamole with everyday painkillers

Your doctor may prescribe (75mg tablets) to take together with dipyridamole. Or your doctor may prescribe dipyridamole instead of daily low dose aspirin if you have problems with aspirin.

Do not take (300mg tablets) or while you're taking dipyridamole unless a doctor has said it's OK to. They increase the chance of bleeding.

You can take together with dipyridamole.

Taking dipyridamole with indigestion medicines

Some indigestion medicines, such as , may reduce the effect of dipyridamole. This is important if you're taking dipyridamole as tablets or liquid, but it's not a problem if you're taking capsules.

If you need to take indigestion medicines, do not take them at the same time of day as dipyridamole. Take them 2 to 3 hours before or after your dose of dipyridamole.

Mixing dipyridamole with herbal remedies and supplements

There might be a problem with taking some herbal remedies and supplements with dipyridamole, especially ones that can affect your blood, for example ginkgo.


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

9. Common questions

How does dipyridamole work?

Dipyridamole slows the blood's clotting action by making platelets less sticky.

Platelets are blood cells that stick together and block cuts and breaks in blood vessels.

However, in people at risk of heart attack or stroke, platelets can stick together inside already-narrowed blood vessels to form a clot. The clot can stop blood flowing to the heart or brain and cause a heart attack or stroke.

If you take it every day, dipyridamole stops platelets from clumping together to form unwanted blood clots. This prevents heart attacks and strokes.

How long does it take to work?

Dipyridamole works within 2 hours of taking it.

When will I feel better?

You may not notice any difference in how you feel after you start taking dipyridamole. This doesn't mean the medicine isn't working.

Carry on taking dipyridamole even if you feel well, as you'll still be getting the benefits.

How long will I take it for?

You will usually need to take dipyridamole for the rest of your life.

Is it safe to take it for a long time?

Dipyridamole is generally safe to take for a long time. In fact, it works best if you take it for many months or years.

What will happen if I stop taking it?

Do not stop taking dipyridamole without talking to your doctor.

If you stop taking dipyridamole, your blood will go back to clotting at the rate it did before, usually within 2 days of stopping the medication. This means you may be at increased risk of serious problems like heart attacks or strokes.

Are there any other similar medicines?

Other antiplatelet medicines include , clopidogrel and ticagrelor.

Anticoagulant medicines such , dabigatran, edoxaban, and are also prescribed as blood thinners.

Not all medicines that prevent blood clots are suitable for everyone. Talk to your doctor or pharmacist to find out why you've been recommended a particular medicine.

Can I drink alcohol with it?

Yes, you can drink alcohol while taking dipyridamole as long as you stick to the national alcohol guidelines of no more than 14 units a week for men and women. A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units.

Both alcohol and dipyridamole can reduce your blood pressure. Together, they can make you feel dizzy or lightheaded. If you find dipyridamole 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 dipyridamole.

Will I need to stop dipyridamole before surgery?

Because of the risk of bleeding, you may need to stop taking dipyridamole a few days before you have an operation. Tell the surgeon that you are taking dipyridamole.

Will I need to stop dipyridamole before surgery?

Because of the risk of bleeding, you may need to stop taking dipyridamole a few days before you have an operation. Tell the surgeon that you are taking dipyridamole.

Can I have vaccinations?

Yes, you can have vaccinations while taking dipyridamole.

Will it affect my contraception or fertility?

Dipyridamole doesn't affect any type of contraception, including the contraceptive pill and the morning after pill.

It doesn't have any effect on male or female fertility.

Will it affect my sex life?

Dipyridamole will not affect your sex life.

Can I drive or ride a bike?

Most people can drive or ride a bike while taking dipyridamole. However, if dipyridamole makes you feel dizzy, don't drive or ride a bike until the dizziness is gone.

Can lifestyle changes help?

If you've been prescribed dipyridamole, you can also improve your health by making some key lifestyle changes.

  • Stop smoking - smoking increases your heart rate and blood pressure. Quitting smoking brings down your risk of heart attack or stroke. Try to avoid secondhand smoke too.
  • Cut down on alcohol - men and women shouldn't drink more than 14 units of alcohol a week.
  • Be more active - regular exercise keeps your heart and blood vessels in good condition. It doesn't need to be too energetic - walking every day can help.
  • Eat healthily - aim to eat a diet that includes plenty of fruit and veg, wholegrains, fat-free or low-fat dairy products, and lean protein. It's a good idea to cut down on salt too. Aim for no more than 6g of salt a day.
  • Manage stress - when you're anxious or upset, your heart beats faster, you breathe more heavily and your blood pressure often goes up. This raises your risk of heart attack and stroke. Find ways to reduce stress in your life. To give your heart a rest, try napping or putting your feet up when possible. Spend time with friends and family to be social and help keep stress at bay.
  • Vaccinations - if you have heart disease, it's recommended you have a flu jab every year and a pneumonia vaccination every 5 years. Ask your doctor about these vaccinations. You can have them free on the NHS.

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Page last reviewed: 29 March 2018
Next review due: 29 March 2021