Garlic and Dipyridamole: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dipyridamole
Garlic
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased risk of bleeding
Interaction Deep Dive
Coadministration of garlic with medications that inhibit platelet aggregation, such as antiplatelet agents, may increase bleeding. Inhibition of platelet aggregation by garlic may be irreversible. Normal hemostasis occurs 7 days after discontinuation of garlic1. Garlic has been shown to inhibit platelet aggregation when taken orally 3. The ability of garlic to affect platelet aggregation depends on the product preparation, with different products containing different active constituents 8.
Why it happens (mechanism)
Additive antiplatelet effects; increased fibrinolysis
Literature reports
3 reports — tap to read
a) The antiplatelet effect of garlic may add to the effect of other antiplatelet agents, increasing the risk for bleeding complications 2. Garlic has been shown to inhibit platelet aggregation when taken orally 3456.
b) Epidural hematoma and other bleeding consequences have been described in case reports when patients consumed garlic without concomitant medications known to affect blood coagulation 7. Given orally to humans, garlic increased fibrinolytic activity possibly through activated plasminogen 6.
c) The ability of garlic to affect platelet aggregation depends on the product preparation, with different products containing different active constituents 8.
Common questions
Can I take Garlic and Dipyridamole together?
Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Garlic and Dipyridamole interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Garlic or Dipyridamole need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (8)
- Kopp SL, Vandermeulen E, McBane RD, et al: Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine evidence-based guidelines (fifth edition). Reg Anesth Pain Med 2025; Epub:Epub.
- Sunter W: Warfarin and garlic. Pharm J 1991; 246:722.
- Kiesewetter H, Jung F, Jung EM, et al: Effects of garlic coated tablets in peripheral arterial occlusive disease. Clin Invest 1993; 71:383-386. PubMed
- Kiesewetter H, Jung F, Jung EM, et al: Effect of garlic on platelet aggregation in patients with increased risk of juvenile ischemia attack. Eur J Clin Pharmacol 1993a; 45:333-336.
- Legnani C, Frascaro M, Gauzzaloca G, et al: Effects of a dried garlic preparation on fibrinolysis and platelet aggregation in healthy subjects. Arzneimittelforschung 1993; 43(2):119-122.
- Harenberg J, Giese C, & Zimmermann R: Effect of dried garlic on blood coagulation, fibrinolysis, platelet aggregation and serum cholesterol levels in patients with hyperlipoproteinemia. Atheroscler 1988; 74(3):247-249. PubMed
- Burnham BE: Garlic as a possible risk for postoperative bleeding. Plast Reconst Surg 1995; 95:213. DOI
- Lawson LD, Ransom DK, Hughes BG, et al: Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic products. Thromb Res 1992; 65:141-156. PubMed
Keep reading about Dipyridamole
Keep reading about Garlic
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