Fig. 5.

Lineweaver-Burk analysis of the inhibitory effect of rolapitant on CYP2D6. Metabolism of dextromethorphan (A) or bufuralol (B) at four different concentrations (5, 10, 50, and 100 µM) was examined in the presence of 0 (◆), 10 (■), 50 (▴), and 100 µM (●) rolapitant. Each data point represents an average of an experiment completed in quadruplicate. In reactions with dextromethorphan and bufuralol, the K_m value increased with increasing concentrations of rolapitant and the V_max value was also affected, indicating mixed inhibition.