Trastuzumab Interactions

7 DRUG INTERACTIONS • Avoid concomitant use of doxorubicin hydrochloride with inhibitors and inducers of CYP3A4, CYP2D6, and/or P-gp ( 7.1 ) • Do not administer doxorubicin hydrochloride in combination with trastuzumab due to increased risk of cardiac dysfunction ( 5.1 , 7.2 ) 7.1 Effect of Other Drugs on Doxorubicin Hydrochloride Injection Inhibitors of CYP3A4, CYP2D6, and P-gp Concomitant use of doxorubicin hydrochloride with inhibitors of CYP3A4, CYP2D6, or P-glycoprotein (P-gp), increased concentrations of doxorubicin, which may increase the incidence and severity of adverse reactions of doxorubicin hydrochloride. 7.2 Concomitant Use of Trastuzumab Concomitant use of trastuzumab and doxorubicin hydrochloride results in an increased risk of cardiac dysfunction. Avoid concomitant administration of Doxorubicin Hydrochloride Injection and trastuzumab [see Warnings and Precautions (5.1) ].

Source: FDA drug label - doxorubicin hydrochloride

Patients receiving ELLENCE after stopping treatment with other cardiotoxic agents, especially those with long half-lives such as trastuzumab, may be at an increased risk of developing cardiotoxicity [see Dosage and Administration (2) and Warnings and Precautions (5.1) ] . Trastuzumab may persist in the circulation for up to 7 months. Therefore, avoid anthracycline-based therapy for up to 7 months after stopping trastuzumab when possible.

Source: FDA drug label - epirubicin hydrochloride

Thiazide diuretics Zidovudine Increased cardiotoxicity may result from a combined effect of cyclophosphamide and, for example: Anthracyclines Cytarabine Pentostatin Radiation therapy of the cardiac region Trastuzumab Increased pulmonary toxicity may result from a combined effect of cyclophosphamide and, for example: Amiodarone G-CSF, GM-CSF (granulocyte colony-stimulating factor, granulocyte macrophage colony-stimulating factor): Reports suggest an increased risk of pulmonary toxicity in patients treated with cytotoxic chemotherapy that includes cyclophosphamide and G-CSF or GMCSF.

Source: FDA drug label - cyclophosphamide