Table 2.

Effects of gefitinib and erlotinib on the disappearance of midazolam and formation of 1-hydroxymidazolam in human liver and intestinal microsomes

Midazolam disappearance rate (% of control)1-Hydroxymidazolam formation rate (% of control)
GefitinibErlotinibImatinibGefitinibErlotinibImatinib
Liver microsomes (μmol/L)
    1119119871289971
    51361347918512974
    201451337020712559
Intestinal microsomes (μmol/L)
    1188145ND13188ND
    5280181ND197135ND
    20352201ND215118ND
  • NOTE: Values are presented as the mean of duplicate determinations. Midazolam initial concentration was 20 μmol/L. The control was midazolam disappearance rate or 1-hydroxymidazolam formation rate in the absence of an effector (e.g., gefitinib, erlotinib, or imatinib). Imatinib (a reported CYP3A inhibitor) was used as the control experiment.