Table 1

Summary of the Ki values for the competitive inhibition of the major human liver P450 isoforms by nelfinavir mesylate

ReactionProbe SubstrateCytochrome P450Ki
μM
6β-HydroxylationTestosteroneCYP3A44.80
4-Hydroxylation S-MephenytoinCYP2C1968.0
O-DemethylationDextromethorphanCYP2D6126
O-DeethylationPhenacetinCYP1A2190
4-HydroxylationTolbutamideCYP2C9nd
6β-HydroxylationChlorzoxazoneCYP2E1nd
6α-HydroxylationPaclitaxelCYP2C8nd

  • Kinetic constants were determined as described in “Materials and Methods.” nd = not determined, as 15 μM nelfinavir inhibited the reaction less than 10%.