Drug General Information (ID: DDI21ANU7E)
Drug Name			Ropinirole		Drug Info		Warfarin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiparkinson Agents				Anticoagulants
Structure

Mechanism of Ropinirole-Warfarin Interaction (Severity Level: Moderate)
Competitive binding of plasma proteins Click to Show/Hide Mechanism Graph
Drug Name		Ropinirole				Warfarin
Mechanism		Competition for plasma protein binding sites				Competition for plasma protein binding sites
Key Mechanism Factor 1
		Factor Name		Plasma protein binding
		Factor Description		Plasma protein binding refers to the degree of binding of a drug to proteins in the blood, and the lower the degree of binding, the more efficiently the drug can cross cell membranes or diffuse. Plasma protein binding alters the distribution and therapeutic characteristics of the drugs.
Mechanism Description		Increased plasma concentration of Warfarin and Ropinirole due to competitive binding of plasma proteins

Recommended Action
Management		Given the potential for interaction and the high degree of interpatient variability with respect to warfarin metabolism, patients should be closely monitored during concomitant therapy with ropinirole. The INR should be checked frequently and warfarin dosage adjusted accordingly, particularly following initiation, discontinuation or change of dosage of ropinirole in patients who are stabilized on their warfarin 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	Bair JD, Oppelt TF "Warfarin and ropinirole interaction." Ann Pharmacother 35 (2001): 1202-4. [PMID: 11675845]