Figure 7.

Plasma concentrations of rofecoxib (mean ± SD) on day 4 of treatment with 25 mg rofecoxib once daily in nine healthy subjects (A). Time 0 refers to the administration of rofecoxib, which was given 1 h before the administration of tizanidine. Relationship between the plasma caffeine/paraxanthine ratio during the placebo phase and the C₀ of rofecoxib (B) and between the plasma caffeine/paraxanthine ratio during the placebo phase and the AUC_0–25 of rofecoxib (C) are also shown. Correlations were tested using linear regression analysis