byetta and Warfarin Interactions

Interactions between byetta(exenatide) and Warfarin (warfarin)

warfarin and exenatide (Moderate Drug-Drug)

MONITOR: Spontaneous reports of increased INR, sometimes accompanied by bleeding, have been associated with concomitant use of warfarin and exenatide. The mechanism of interaction is unknown. In a controlled study in healthy volunteers, the time to reach peak plasma concentration (Tmax) of warfarin was delayed by about two hours when warfarin was administered 30 minutes after exenatide. However, no clinically relevant effects on peak plasma concentration (Cmax) or systemic exposure (AUC) were observed.

MANAGEMENT: Until more data are available, caution is advised if exenatide is prescribed to patients treated with warfarin. The INR should be checked frequently and warfarin dosage adjusted accordingly, particularly following initiation or discontinuation of exenatide in patients who are stabilized on their warfarin regimen. The same precaution may be applicable during therapy with other oral anticoagulants, although clinical data are lacking. 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.