Figure 4.

Plasma fentanyl concentrations and pupil diameter during the pharmacokinetically tailored IV infusion in the placebo (blue squares for concentration, blue triangles for pupil diameter) and St. John’s wort (red circles for concentration, red diamonds for pupil diameter) groups. Solid symbols represent St. John’s wort/placebo pre-treatment values and open symbols post-treatment values. Solid green line denotes the target plasma fentanyl at 1 ng/mL, and dashed green line represents the overall predicted pupil diameter based upon the baseline pupil diameter, achieved plasma fentanyl, and EC₅₀ derived from the fixed-dose fentanyl study day for all 32 subject-days. Results are the mean ± SD.