FIG. 5.

Inhibitory effect of INH on CYP2C9-catalyzed 4-methylhydroxylation and flurbiprofen 4-hydroxylation. (A) Inhibition of CYP2C9 (with tolbutamide [TB] [20 and 40 μM] and flurbiprofen [FB] [13 and 25 μM] as substrates) by INH (0 to 250 μM) in HLMs; (B) Dixon plots for the inhibition by INH of CYP2C9 (with tolbutamide) in recombinant human CYP2C9; (C) inhibitory effect of INH (0 to 250 μM) on CYP2C9 (with tolbutamide [50 μM]) with preincubation (PI) or without preincubation in HLMs (see Materials and Methods for details). Data are averages for duplicate incubations.