Dipyridamole

Dipyridamole prevents platelet clumping and is used with warfarin (Coumadin®) to prevent blood clots from forming after heart valve replacement. It may be used alone or combined with aspirin to prevent strokes.

Summary of Interactions with Vitamins, Herbs, and Foods
(for details about the summarized interactions, read the full article)

May be Beneficial: Depletion or interference—The medication may deplete or interfere with the absorption or function of the nutrient. Taking these nutrients may help replenish them.	Iron*
May be Beneficial: Supportive interaction—Taking these supplements may support or otherwise help your medication work better.	Garlic*
Check: Other—Before taking any of these supplements or eating any of these foods with your medication, read this article in full for details.	Caffeine
Side effect reduction/prevention	None known
Reduced drug absorption/bioavailability	None known
Adverse interaction	None known

Interactions with Dietary Supplements

Iron
Some studies suggest the taking of too much iron by individuals who are not iron deficient can result in tissue damage that may contribute to heart disease.¹ Test tube studies have shown dipyridamole blocks platelet clumping caused by iron,² which might reduce the damage caused by this mineral. Controlled human studies are needed to test this possibility.

Interactions with Herbs

Garlic (Allium sativa)
A test tube study has shown ajoene, a compound found in garlic that prevents platelet clumping, enhances the beneficial action of dipyridamole on human platelets.³ Controlled research is needed to determine whether taking garlic supplements together with dipyridamole might enhance the effectiveness of either compound taken alone.

Interactions with Foods and Other Compounds

Coffee and Caffeine
Taking dipyridamole can cause a reduction in the amount of oxygen delivered to the heart, resulting in a rare side effect known as angina pectoris. Because dipyridamole has this effect, it has sometimes been used in heart stress tests. One person who consumed coffee prior to the test failed to experience the expected reduction in blood flow caused by dipyridamole.⁴ Controlled studies are needed to determine whether consumption of beverages containing caffeine might reduce the likelihood of developing angina from the drug.

References

1. Tzonou A, Lagiou P, Trichopoulou A, et al. Dietary iron and coronary heart disease risk: a study from Greece. Am J Epidemiol 1998;147:161–6.

2. De la Cruz JP, Garcia PJ, Sanchez de la Cuesta F. Dipyridamole inhibits platelet aggregation induced by oxygen-derived free radicals. Thromb Res 1992;66:277–85.

3. Apitz-Castro R, Escalante J, Vargas R, Jain MK. Ajoene, the antiplatelet principle of garlic, synergistically potentiates the antiaggregatory action of prostacyclin, forskolin, indomethacin and dipyridamole on human platelets. Thromb Res 1986;42:303–11.

4. Smits P, Aengevaeren WR, Corstens FH, Thien T. Caffeine reduces dipyridamole-induced myocardial ischemia. J Nucl Med 1989;30:1723–6.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires July 2004.