TABLE 3

Effect of efavirenz on P450 2B6 catalytic activity, P450 content as measured by the reduced CO spectrum, and heme before and after 24 h of dialysis The assays were performed as described under Materials and Methods. Samples were incubated for 15 min in the presence or absence of NADPH, and the data are represented as percentages of the control samples incubated in the absence of efavirenz. Samples were then dialyzed for 24 h. The data represent the means and S.D. of three separate experiments.


Primary Reaction Conditions

% Control
Activity Remaining
Reduced CO Remaining
HPLC Heme
Before dialysis
   – Efavirenz + NADPH 100 100 100
   + Efavirenz + NADPH 32 ± 3 35 ± 4 31 ± 2
After dialysis
   – Efavirenz + NADPH 100 100 100
   + Efavirenz + NADPH
98 ± 5
96 ± 4
101 ± 3