Table 4

Effects of riluzole (1 and 10 μM) on human hepatic cytochrome P450-mediated oxidative drug metabolism

Drug oxidationP450 isoenzymeChange in drug metabolism
Low substrate concentration4-aHigh substrate concentration4-a
1 μM riluzole10 μM riluzole1 μM riluzole10 μM riluzole
%
Phenacetin-O-deethylationCYP1A2+5−190−12
Coumarin-7-hydroxylationCYP2A6−13−17−2−2
Tolbutamide-4-hydroxylationCYP2C9+6+3+10+4
S-Mephenytoin-4-hydroxylationCYP2C19+1−2−1+3
Bufuralol-1-hydroxylationCYP2D6−9−14−11−14
Chlorzoxazone-6-hydroxylationCYP2E1−5−28−7−20
Nifedipine dehydrogenationCYP3A4−15+4−4+8
  • 4-a Substrate concentrations: nifedipine, 25 and 50 μM; chlorzoxazone, 40 and 80 μM; bufuralol, 15 and 30 μM;S-mephenytoin, 100 and 200 μM; tolbutamide, 125 and 250 μM; coumarin, 0.5 and 1 μM; phenacetin, 40 and 100 μM.

  • +, Enhancement of drug metabolism; −, inhibition of drug metabolism.

  • Results are expressed as the mean values for two human liver samples.