Alteration in Cyp3a11 and Abcb1a gene expression by dexamethasone, efavirenz, ketoconazole, or ritonavir when administered in combination with docetaxel at 0.5 hr (A) and 6 hr (B). The fold-change was normalized to the compared to the control arm. The bars represent the mean, while the standard deviation is noted with the error bars. **, P < 0.05 vs. all groups, Wilcoxon signed rank with post hoc analysis.