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Diabetes Mellitus
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Antiplatelet Agents
Dipyridamole-containing Medications
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Look Up > Herbs > Garlic > Interactions
Interactions with Garlic
Dipyridamole; Indomethacin; Warfarin

Ajoene, the active antiplatelet component in garlic, potentiated the effect of physiologically and pharmacologically active antiplatelet agents such as dipyridamole and indomethacin in vitro (Apitz-Castro et al. 1986).

When administered to patients with myocardial infarction, the essential oil of garlic increased fibrinolysis by 63% to 69%, thereby enhancing the activity of warfarin (Bordia et al. 1977). Two cases of a possible interaction between warfarin and garlic have been reported in patients stabilized on anticoagulant therapy (Stockley 1999). In one case, the patient's INR values more than doubled and there was an incident of hematuria eight weeks after ingestion of garlic (3 pearles/day). This situation resolved when the garlic was discontinued, but the INR rose again when the patient started taking two garlic tablets daily. In the other case, the patient's INR also increased more than two-fold while the patient was taking garlic (6 tablets/day). Because of its antiplatelet and antithrombotic activity, garlic should be used with caution in patients taking oral anticoagulants (Rose et al. 1990).


Apitz-Castro R, Escalante J, Vargas R, et al. Ajoene, the antiplatelet principle of garlic, synergistically potentiates the antiaggregatory action of prostacyclin, forskolin, indomethacin, and dipyridamole on human platelets. Thromb Res. 1986;42(3):303-311.

Bordia AK, Joshi JK, Sanadhya YD, et al. Effect of essential oil of garlic on serum fibrinolytic activity in patients with coronary artery disease. Atheroscl. 1977;28:155-159.

Rose KD, Croissant PD, Parliamennt CF, et al. Spontaneous spinal epidural hematoma with associated liver dysfunction from excessive garlic ingestion: a case report. Neurosurg. 1990;26:880-882.

Stockley IH. Drug Interactions, 5th ed. London, England: Pharmaceutical Press; 1999:240-241.

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