TABLE 3

Stereospecific risk assessment of the inhibition of CYP2C19 and CYP3A4 after fluoxetine administration

The predicted values are shown for the change in in vivo enzyme activity from before to after fluoxetine administration due to reversible (Imax/IC50) and time-dependent (λ/kdeg) inhibition.

CYP2C19CYP3A4
Imax/IC50λ/kdegImax/IC50λ/kdeg
(R)-Fluoxetine0.035.8<0.01NA
(S)-Fluoxetine<0.011.2<0.010.5
(R)-Norfluoxetine<0.012.90.011.1
(S)-Norfluoxetine0.029.4<0.01NA
  • NA, not applicable.