Dipyridamole: Formula, Indications, Mechanism of Action, Dosage, Side Effects, Warnings, Contraindications and Interactions

It belongs to the class of platelet aggregation inhibitors or antiplatelet agents.

Dipyridamole prevents certain types of blood cells, called platelets, from sticking together.

It is also used for specific heart tests that look at how well blood flows through the heart.

Chemical formula

  • C24H40N8O4.


This medicine is available in 25 mg, 50 mg, and 75 mg tablets.


Dipyridamole is an adjunct to oral anticoagulants to prevent thrombosis in prosthetic heart valves.

It is used to prevent blood clots after a heart valve replacement.

Mechanism of action

Dipyridamole selectively dilates the vessels that supply blood to the heart, increasing coronary blood flow.


Dipyridamole is a potent coronary vasodilator and platelet aggregation inhibitor. This action can inhibit the absorption of adenosine both in platelets, endothelial cells, and erythrocytes.


In children

The use of this medicine is not recommended in children.

In adults

The recommended oral dose of dipyridamole in adults to prevent blood clots is 300 to 600 mg daily in three or four doses before meals. If taken with 1 g of ASA a day, the dipyridamole dose can be reduced to 25 mg 4 times a day.

When dipyridamole is used for medical tests that examine blood flow through the heart, dipyridamole is given intravenously in a hospital.

Side effects

Dipyridamole side effects can be mild or severe, temporary or permanent:

  • Gastrointestinal upset with abdominal or stomach cramps.
  • Diarrhea.
  • Dizziness or lightheadedness
  • Redness and rash.
  • Headaches
  • Nausea or vomiting
  • Certain weakness.

The doctor should be consulted as soon as possible if the patient has any of the following serious side effects:

  • Gallstones
  • Yellow eyes or skin.
  • Chest pain.
  • Increased heart rate.
  • Low blood pressure (symptoms may include dizziness or fainting).
  • Signs of a severe allergic reaction (such as hives, difficulty breathing, or swelling of the face or throat).
  • Unusual bleeding or bruising.

Warnings and Contraindications

Dipyridamole should not be taken if the patient is allergic to dipyridamole or any ingredient in the drug.

Dipyridamole in the injectable form of this medicine should not be given to anyone who is in shock or collapsed.

Dipyridamole should be administered with great caution in patients with low blood pressure. This drug can lower blood pressure and increase the effectiveness of other medications used to lower blood pressure.

This medication should not be used during pregnancy unless the benefits outweigh the risks. The doctor should be informed if the patient is pregnant or planning to become pregnant before taking this medicine.

Dipyridamole is a drug that is excreted through breast milk. So you should not breastfeed if you are taking dipyridamole because it can affect the infant. The safety and efficacy of using this medicine have not been established for children.

Dipyridamole should not be administered if the patient has severe coronary artery disease, including unstable angina, recent myocardial infarction, left ventricular outflow obstruction, hemodynamic instability, biliary disorders, bleeding disorders, and myasthenia gravis.


Dipyridamole can interact with medications such as:

  • Adenosine.
  • Aminophylline (in injectable form).
  • Medicines are used to lower blood pressure.
  • Blood thinners such as warfarin.
  • Cholinesterase inhibitors such as donepezil and rivastigmine.
  • Colchicine.
  • El dabigatran.
  • El drotrecogin.
  • El everolimus.
  • Theophylline in injectable form.
  • El topotecan.
  • The alcohol.

The interaction between the concomitance of two drugs does not necessarily mean that they should be discontinued.

The doctor may recommend that the patient discontinue one of the medications, replace one, or change the doses or how one or both medications are being taken.