Retrospective analysis of severe neutropenia in patients receiving concomitant administration of docetaxel and clarithromycin.

Background: Neutropenia is one of the most important dose-limiting toxicities of docetaxel. Docetaxel is metabolized by cytochrome P450 3A4 (CYP3A4). Clarithromycin, a potent inhibitor of CYP3A4, is occasionally used in combination with docetaxel.