In vitro studies have shown that the metabolism of docetaxel may be modified by concomitant administration of compounds that induce, inhibit, or are metabolized by cytochrome P450 3A4, such as cyclosporine, ketoconazole, erythromycin and troleandomycin. Exercise caution with these drugs when treating patients receiving docetaxel, as there is a potential for a significant interaction. Based on in vitro findings, it is likely that CYP3A4 inhibitors and/or substrates may lead to substantial increases in docetaxel blood concentrations.