Pharmacokinetics of dexamethasone and valspodar, a P-glycoprotein (mdr1) modulator: implications for coadministration.

Study Objective: To assess the potential for a drug-drug interaction between valspodar, a P-glycoprotein (mdrl) modulator used as a chemotherapy adjunct, and dexamethasone, widely included in oncology antiemetic regimens.

Design: Randomized, open-label, three-period crossover study.

Setting: Clinical pharmacology research center.