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Dipyridamole to prevent blood clots


Dipyridamole helps prevent blood clots forming in arteries. This reduces the risk of heart attack and stroke.

Do not take indigestion remedies at the same time of day as your dose of dipyridamole.

If you buy any medicines for cold or pain relief, check with a pharmacist first to make sure they do not contain aspirin.

Side-effects tend to be mild and occur more frequently at the beginning of treatment. The most common are headache, feeling sick (nausea), flushing, and feeling dizzy.

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About dipyridamole

Type of medicine

Antiplatelet medicine

Used for

To prevent clots forming in blood vessels after heart valve replacement, or a previous stroke

Also called


Available as

Tablets, modified-release capsules and oral liquid medicine

In your blood there are 'sticky' cells called platelets. When you cut yourself, the platelets stick to each other (clot) to seal the wound. Sometimes platelets stick to each other inside a blood vessel - this is called a thrombus. A thrombus can block a blood vessel, and this is often the cause of a stroke or heart attack. This is more likely to happen if you have had surgery to replace a heart valve, or if you have blood vessel disease (for example, if you have had a stroke or a transient ischaemic attack).

Dipyridamole reduces the 'stickiness' of platelets. It will help to prevent a thrombus forming in an artery, which will reduce the risk of you having a heart attack or a stroke. It is often prescribed alongside other medicines to prevent blood clots. One such medicine is aspirin, which is another antiplatelet medicine.

Before taking dipyridamole

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking dipyridamole it is important that your doctor knows:

  • If you are pregnant or breastfeeding.

  • If you have angina, or any other heart condition or circulation problem.

  • If you have low blood pressure.

  • If you have any bleeding problems.

  • If you have migraines, or if you have a muscle-weakening disease called myasthenia gravis. Dipyridamole can make these conditions worse.

  • If you have ever had an allergic reaction to a medicine.

  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

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How to take dipyridamole

  • Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. The leaflet will give you more information about dipyridamole and a full list of side-effects which you may experience from taking it.

  • Take dipyridamole exactly as your doctor tells you to. Your doctor or pharmacist will tell you how much to take and when to take it, and this information will also be printed on the label of the pack to remind you. As a guide, if you have been prescribed dipyridamole tablets, you will need to take three or four doses daily. If you have been prescribed dipyridamole capsules, you will need to take two doses daily, usually in the morning and the evening.

  • There is an important difference in the way dipyridamole tablets and dipyridamole capsules are taken. If you have been supplied with tablets, take your doses 30-60 minutes before a meal. If you have been supplied with capsules, take your doses at the same time as a meal, or shortly afterwards.

  • It can help to take your doses with a drink of water. Swallow the tablets/capsules whole - this means do not crush or chew the tablets, or open the capsules.

  • Try to take your doses at the same times of day, each day. This will help you to remember to take them.

  • If you do forget to take a dose, take it as soon as you remember, unless it is nearly time for your next dose, in which case leave out the forgotten dose. Do not take two doses together to make up for a missed dose.

Getting the most from your treatment

  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.

  • If you buy any medicines, check with a pharmacist that they are suitable for you to take. For example, some indigestion remedies can interfere with the way your body absorbs dipyridamole, so they should not be taken at the same time of day. Also, it is recommended that you do not take any preparations containing aspirin without checking this first with your doctor. Several medicines for pain relief and cold relief that can be bought at retail outlets contain aspirin, so check the label carefully before you buy.

  • If you are having an operation or any medical treatment, tell the person carrying out the treatment that you are taking dipyridamole.

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Can dipyridamole cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with dipyridamole. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.


dipyridamole side-effects - these affect fewer than 1 in 10 people who take this medicine

What can I do if I experience this?

Feeling sick (nausea), diarrhoea

Stick to simple foods - avoid rich or spicy meals. Drink plenty of water to replace any lost fluids

Feeling dizzy or faint, particularly when standing up

Try getting up and moving more slowly. If you begin to feel dizzy, sit down until you feel better

Headache, muscle pains

Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If either of these continue, speak with your doctor

Flushed face

This should soon settle. If it becomes troublesome, speak with your doctor

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store dipyridamole

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

  • Capsules should be kept in the original container and any remaining capsules discarded six weeks after opening the container.

  • The oral liquid medicine lasts for one to two months after first opening, depending on which brand you have been given. Check the manufacturer's leaflet that comes with your medicine.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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