Interaction of epirubicin with other cytotoxics and anti-emetic drugs.

Epirubicin is usually administered in combination with other cytotoxics. Few pharmacological studies address whether relevant clinical interactions occur in vitro between these drugs. This study investigated whether epirubicin interacted with other cytotoxics or anti-emetics. The following drugs were prepared at pharmacological concentrations, etoposide (200 micrograms/ml), 5-fluorouracil (120 micrograms/ml), cisplatin (100 micrograms/ml), vincristine (100 micrograms/ml) and cyclophosphamide (1 micrograms/ml) respectively were admixed with epirubicin (1 micrograms/ml). Epirubicin was analysed by high performance liquid chromatography using in-line UV and fluorescence detectors. Experiments were performed in quadruplicate. No significant interactions were noted. The experiments were repeated for stemetil and maxolon. Maxolon did not interact with epirubicin but stemetil produced an interfering peak in the assay. We conclude that interaction studies are an important step in the workup of chemotherapy regimens.