Fig. 6. Ritonavir/indinavir effects on oral methadone disposition. Shown are plasma ( A, B ) R-methadone and R-EDDP (2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolidine) concentrations and ( C, D ) S-methadone and S-EDDP concentrations. Subjects received 11.0 mg of oral methadone HCl (9.9 mg free base). Each data point is the mean ± SD (n = 12). Some SD are omitted for clarity.