Drug General Information (ID: DDIUPZY2DE)
  Drug Name Warfarin Drug Info Vorinostat Drug Info
  Drug Type Small molecule Small molecule
  Therapeutic Class Anticoagulants Antineoplastics
  Structure

 Mechanism of Warfarin-Vorinostat Interaction (Severity Level: Moderate)
     Increased risk of bleeding Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Warfarin Vorinostat
      Mechanism Vitamin K antagonist Potentiate the hypoprothrombinemic effect of vitamin K antagonist
      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 Vorinostat 

Recommended Action
      Management Patients treated with a coumarin-derivative anticoagulant should be closely monitored during concomitant therapy with histone deacetylase inhibitors such as romidepsin and vorinostat. The INR should be checked frequently and anticoagulant dosage adjusted accordingly, particularly following initiation, discontinuation or change of dosage of the histone deacetylase inhibitor in patients who are stabilized on their anticoagulant regimen. 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 Guo LQ, Yamazoe Y "Inhibition of cytochrome P450 by furanocoumarins in grapefruit juice and herbal medicines." Acta Pharmacol Sin 25 (2004): 129-36. [PMID: 14769198]
2 Product Information. Istodax (romidepsin). Gloucester Pharmaceuticals, Cambridge, MA.
3 Product Information. Zolinza (vorinostat). Merck &amp Company Inc, West Point, PA.