Abstract

Dipyridamole (trademarked as Persantine and others) is a medication that inhibits blood clot formation when given chronically and causes blood vessel dilation when given at high doses over a short time.

Medical uses | Use in individuals with a history of stroke

A combination of dipyridamole and aspirin (acetylsalicylic acid/dipyridamole) is FDA-approved for the secondary prevention of stroke and has a bleeding risk equal to that of aspirin use alone. Dipyridamole absorption is pH-dependent and concomitant treatment with gastric acid suppressors (such as a proton pump inhibitor) will inhibit the absorption of liquid and plain tablets. Modified release preparations are buffered and absorption is not affected.

However, it is not licensed as monotherapy for stroke prophylaxis, although a Cochrane Review suggested that dipyridamole may reduce the risk of further vascular events in patients presenting after cerebral ischemia.

A triple therapy of aspirin, clopidogrel, and dipyridamole has been investigated, but this combination led to an increase in adverse bleeding events.

- Vasodilation occurs in healthy arteries, whereas stenosed arteries remain narrowed. This creates a "steal" phenomenon where the coronary blood supply will increase to the dilated healthy vessels compared to the stenosed arteries which can then be detected by clinical symptoms of chest pain, electrocardiogram and echocardiography when it causes ischemia.

- Flow heterogeneity (a necessary precursor to ischemia) can be detected with gamma cameras and SPECT using nuclear imaging agents such as Thallium-201, Tc99m-Tetrofosmin and Tc99m-Sestamibi. However, relative differences in perfusion do not necessarily imply any absolute decrease in blood supply in the tissue supplied by a stenosed artery.

Medical uses | Other uses

Dipyridamole also has non-medicinal uses in a laboratory context, such as the inhibition of cardiovirus growth in cell culture.

Overdose

Dipyridamole overdose can be treated with aminophylline which reverses its dilating effect on the blood vessels. Symptomatic treatment is recommended, possibly including a vasopressor drug. Gastric lavage should be considered. Administration of xanthine derivatives (e.g., aminophylline) may reverse the hemodynamic effects of dipyridamole overdose. Since dipyridamole is highly protein bound, dialysis is not likely to be of benefit.