Drug General Information (ID: DDIPB7X9SR)
Drug Name			Warfarin		Drug Info		Heparin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Anticoagulants				Anticoagulants
Structure

Mechanism of Warfarin-Heparin Interaction (Severity Level: Major)
Increased risk of bleeding Click to Show/Hide Mechanism Graph
Drug Name		Warfarin				Heparin
Mechanism		Risk of bleeding Anticoagulant				Risk of bleeding Anticoagulant
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 Heparin

Recommended Action
Management		During concurrent or overlapping therapy, close clinical and laboratory observation for hematologic complications is recommended. To minimize the interference of heparin on INR determinations, blood should not be drawn until at least 5 hours after the last intravenous heparin dose or 24 hours after the last subcutaneous heparin dose.

References
1	Product Information. Coumadin (warfarin). DuPont Pharmaceuticals, Wilmington, DE.
2	Product Information. Heparin Sodium (heparin). Lilly, Eli and Company, Indianapolis, IN.