Drug Interaction Report

MONITOR: Coadministration of alemtuzumab with antiplatelet or anticoagulant drugs may increase the risk of bleeding. Use of alemtuzumab alone has been associated with autoimmune and hemolytic anemia, thrombocytopenia, prolonged myelosuppression, bone marrow aplasia, hemophilia, and pancytopenia. The mechanism for this interaction has not been clearly delineated, but is presumably due to additive antiplatelet/anticoagulant effects.

MANAGEMENT: Caution is recommended if alemtuzumab is used concomitantly with antiplatelet or anticoagulant drugs. Patients should be monitored for increased anticoagulant effects and bleeding complications. Patients should be advised to promptly report any signs of unusual bleeding or bruising to their physician, including pain, swelling, headache, dizziness, weakness, prolonged bleeding from cuts, increased menstrual flow, vaginal bleeding, nosebleeds, bleeding of gums from brushing, red or brown urine, or red or black stools.

ADJUST DOSING INTERVAL: Food reduces the oral bioavailability of betrixaban. When administered with a low-fat (900 calories; 20% fat) or high-fat (900 calories; 60% fat) meal, betrixaban peak plasma concentration (Cmax) and systemic exposure (AUC) decreased relative to administration in the fasting state by an average of 70% and 61%, respectively, with the low-fat meal and 50% and 48%, respectively, with the high-fat meal. The effect of food on betrixaban pharmacokinetics could be observed for up to 6 hours after meal intake.

MANAGEMENT: The manufacturer recommends taking betrixaban at the same time each day with food.