Drug General Information (ID: DDI7G5JF39)
Drug Name			Warfarin		Drug Info		Oxacillin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Anticoagulants				Antibiotics
Structure

Mechanism of Warfarin-Oxacillin Interaction (Severity Level: Moderate)
Increased risk of bleeding Click to Show/Hide Mechanism Graph
Drug Name		Warfarin				Oxacillin
Mechanism		Risk of bleeding Anticoagulant				Risk of bleeding Antiplatelet effects
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 Oxacillin

Recommended Action
Management		Caution is recommended if a penicillin is prescribed during oral anticoagulant therapy, especially in the elderly and patients with uremia or hepatic impairment. The INR should be checked frequently and anticoagulant dosage adjusted accordingly, particularly following initiation or discontinuation of penicillin therapy in patients who are stabilized on their anticoagulant regimen. Patients should be advised to promptly report any signs of bleeding to their doctor, 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
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