Drug General Information (ID: DDIMJSC2RP)
  Drug Name Warfarin Drug Info Dipyridamole Drug Info
  Drug Type Small molecule Small molecule
  Therapeutic Class Anticoagulants Vasodilator Agents
  Structure

 Mechanism of Warfarin-Dipyridamole Interaction (Severity Level: Moderate)
     Increased risk of bleeding Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Warfarin Dipyridamole
      Mechanism Risk of bleeding
Anticoagulant 
Risk of bleeding
Antiplatelet 
      Key Mechanism Factor 1
Factor Name Bleeding
Factor Description Patients may be at risk for bleeding when the outcome of a disease or disease treatment confounds the standard mechanisms for maintaining hemostasis. Signs or symptoms of abnormal bleeding include: bleeding that takes a long time to stop (including nosebleeds, bleeding gums, bleeding from cuts and abrasions, and menstrual bleeding); severe unexplained bruising, or bruising that becomes larger; blood in the urine or stool, etc.
      Mechanism Description
  • Increased risk of bleeding by the combination of Warfarin and Dipyridamole 

Recommended Action
      Management Monitoring for signs of increased anticoagulation and bleeding may be advisable during coadministration of dipyridamole and oral anticoagulants. Patients should be advised to promptly report any signs of bleeding to their physician, including pain, swelling, headache, dizziness, weakness, prolonged bleeding from cuts, increased menstrual flow, vaginal bleeding, nosebleeds, bleeding of gums from brushing, unusual bleeding or bruising, red or brown urine, or red or black stools.

References
1 Donaldson DR, Sreeharan N, Crow MJ, Rajah SM "Assessment of the interaction of warfarin with aspirin and dipyridamole." Thromb Haemost 47 (1982): 77. [PMID: 6978549]
2 Haworth E, Burroughs AK "Disopyramide and warfarin interaction." Br Med J 2 (1977): 866-7. [PMID: 922330]
3 Massel D, Little SH "Risks and benefits of adding anti-platelet therapy to warfarin among patients with prosthetic heart valves: A meta-analysis." J Am Coll Cardiol 37 (2001): 569-78. [PMID: 11216981]
4 Product Information. Persantine (dipyridamole). Boehringer-Ingelheim, Ridgefield, CT.
5 Rhodes RS, Rhodes PJ, Klein C, Sintek CD. A warfarin-piroxicam drug interaction.?Drug Intell Clin Pharm. 1985;19(7-8):556-558. [PMID: 4028961]
6 Sylven C, Anderson P "Evidence that disopyramide does not interact with warfarin." Br Med J 286 (1983): 1181. [PMID: 6404381]