Drug Interaction Report

MONITOR CLOSELY: Coadministration of radiolabeled ibritumomab tiuxetan and drugs that interfere with platelet function or coagulation may potentiate the risk of bleeding complications. Radiolabeled ibritumomab tiuxetan commonly causes severe and prolonged thrombocytopenia, and the risk is increased further in patients with mild thrombocytopenia at the initiation of therapy. Haemorrhage, including fatal cerebral hemorrhage, has occurred in a minority of patients in clinical studies. The median time to thrombocyte nadir was 7 to 9 weeks, and the median duration of thrombocytopenia was 22 to 35 days. However, in less than 5% of the cases, patients experienced severe cytopenia that extended beyond 12 weeks following administration of the radiolabeled ibritumomab tiuxetan therapeutic regimen. Platelet transfusions were given to 22% of patients in clinical trials.

MANAGEMENT: Caution is advised if radiolabeled ibritumomab tiuxetan is used in combination with drugs that interfere with platelet function or coagulation. Close clinical and laboratory observation for bleeding complications is recommended during and after treatment.

GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.

MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.