Drug Interaction Report

GENERALLY AVOID: The use of trastuzumab and anthracyclines in combination has been associated with a high risk of cardiotoxicity. Trastuzumab and agents in the anthracycline class are individually cardiotoxic and may have additive effects during coadministration. Since trastuzumab has a half-life of approximately 28 to 38 days, it may persist in the circulation for up to 27 weeks after stopping treatment. Thus, the use of anthracyclines after stopping trastuzumab may also carry a higher risk of cardiac toxicity.

MANAGEMENT: Trastuzumab and cardiotoxic agents such as anthracyclines should not be used in combination except in settings where cardiac monitoring is possible. The use of anthracycline-based therapy should be avoided, if possible, for up to 7 months after stopping trastuzumab. If anthracyclines must be used sooner, the patient's cardiac function should be closely monitored.