|Main use||Active ingredient||Manufacturer|
|Preventing blood clots||Dipyridamole||Boehringer Ingelheim|
How does it work?
Persantin tablets contain the active ingredient dipyridamole, which is a type of medicine known as an antiplatelet. It prevents blood cells called platelets from clumping together inside the blood vessels, and is sometimes referred to as a 'blood thinner'. It also dilates the blood vessels. (NB. Dipyridamole is also available without a brand name, ie as the generic medicine.)
Platelets are the blood cells that start off the process of blood clotting. Blood clots normally only form to stop bleeding that has occurred as a result of injury to the tissues. The process is complicated and begins when platelets stick to the site of damage and clump together. They then produce chemicals that attract more platelets and clotting factors to the area, and eventually a solid clot is formed. This is the bodys natural way of repairing itself.
Sometimes, however, a blood clot can form inside the blood vessels. This is known as a thrombus and can be dangerous because the clot may detach and travel in the bloodstream (thomboembolism). It may eventually get lodged in a blood vessel, thereby blocking the blood supply to a vital organ such as the brain. This can cause a stroke or mini-stroke (transient ischaemic attack).
Some people have an increased tendency for blood clots to form within the blood vessels. This is usually due to a disturbance in the blood flow within the blood vessels. For example, fatty deposits on the walls of the blood vessels (atherosclerosis) can disrupt the blood flow, giving a tendency for platelets to clump together and start off the clotting process. People with heart valve disease who have had an artificial heart valve inserted are also at increased risk of blood clots, because platelets can stick to the artificial valve. This may lead to a blood clot forming on the valve, which could then detach and travel to the brain, causing a stroke.
Dipyridamole is used to prevent platelets from forming blood clots. It works by blocking the action of an enzyme found in platelets called phosphodiesterase. Inside the platelets phosphodiesterase normally breaks down a chemical called cyclic AMP. Cyclic AMP plays a key role in blood clotting. If the level of cyclic AMP in the platelets is high this prevents the platelets from clumping together. Dipyridamole causes the levels of cyclic AMP in the platelets to rise, because it stops phosphodiesterase from breaking it down. This means that dipyridamole stops the platelets from clumping together and causing a blood clot.
Dipyridamole is used to prevent blood clots forming on artificial heart valves. It is used in combination with an anticoagulant medicine such as warfarin, which prevents blood clots in a different way. The combination of medicines reduces the chance of a clot forming on the valve and then detaching and travelling in the blood vessels.
What is it used for?
- Preventing dangerous blood clots (thromboembolism) in people with artificial heart valves.
- Dipyridamole is sometimes given by injection during certain types of diagnostic tests to check if the heart is functioning properly. However, dipyridamole injection should not usually be given to people who are taking dipyridamole by mouth. If you are due to have any tests on your heart, you should make sure the doctor knows you are taking this medicine, as they may want you to stop taking it 24 hours before the test.
Use with caution in
- Severe coronary artery disease.
- Angina not well controlled by medical treatment (unstable angina).
- People who have recently had a heart attack.
- Narrowing of the main artery coming from the heart (aortic stenosis).
- Heart failure.
- Low blood pressure (hypotension).
- Abnormal muscle weakness (myasthenia gravis).
- Blood clotting disorders.
Not to be used in
- Known sensitivity or allergy to any ingredient.
- This medicine is not recommended for use in children.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine is not known to be harmful if used during pregnancy. However, as with all medicines, it should be used with caution during pregnancy, and only if the expected benefit to the mother is greater than any possible risk to the developing baby. This is particularly important in the first trimester. Seek medical advice from your doctor.
- This medicine may pass into breast milk in small amounts. It should not be used during breastfeeding unless considered essential by your doctor. Seek medical advice from your doctor.
- Take this medication half to one hour before food.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
- Nausea and vomiting.
- Feeling faint.
- Indigestion (dyspepsia).
- Throbbing headache (normally disappears with long-term use).
- Pain in the muscles (myalgia).
- Hot flushes.
- Faster than normal heart beat (tachycardia).
- Low blood pressure (hypotension).
- Temporary worsening of chest pain (angina) at the start of therapy.
- Increased bleeding during or after surgery.
- Allergic reactions such as skin rash, hives, narrowing of the airways (bronchospasm), or swelling of the lips, tongue and throat (angioedema).
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.
Dipyridamole enhances the anti-blood-clotting effect of the following medicines:
- anticoagulants, eg warfarin
- other antiplatelet medicines, eg low-dose aspirin, clopidogrel.
Antacids for indigestion and heartburn may reduce the absorption of dipyridamole from the gut. As this could make it less effective, antacids should preferably not be taken in the two hours before or after taking this medicine.
Dipyridamole increases the effect of a medicine for irregular heart beats called adenosine. The dose of adenosine needed in people taking dipyridamole will be much lower than normal.
Dipyridamole may decrease the effect of the anti-cancer medicine fludarabine.
Other medicines containing the same active ingredient
Dipyridamole tablets and suspension are also available without a brand name, ie as the generic medicine.