Drug Interaction Report

MONITOR: Coadministration of an antifibrinolytic agent (e.g., aminocaproic acid, tranexamic acid, aprotinin) in combination with a tissue plasminogen activator (t-PA) may reduce the therapeutic effects of both drugs due to opposing pharmacodynamic actions. Aminocaproic acid and tranexamic acid are competitive inhibitors of plasminogen activation. At high concentrations they can also directly inhibit plasmin, which is needed for the degradation of fibrin and thrombolysis. Aprotinin is a broad-spectrum protease inhibitor that inhibits plasmin. It is known to have antifibrinolytic activity and may interact with t-PAs in a similar fashion.

MANAGEMENT: No specific intervention is warranted, but clinicians should be alert to the potential for diminished therapeutic efficacy if a tissue plasminogen activator is administered to a patient who has been treated with an antifibrinolytic agent, and vice versa.