Table 3.
Regression equations describing the relationship between methadone pharmacokinetic parameters and covariates retained in the Full Covariate model
| Mean (SD) regression coefficient | |||
|---|---|---|---|
| Patient characteristic | Rac-methadone | (R)-methadone | (S)-methadone |
| Vc/F (l) = θ1 + θ2sex + θ3AAG | θ1: 146 | θ1: 182 | θ1: 128 |
| θ2: 25 (4.1) | θ2: 33 (5.1) | θ2: 21 (3.5) | |
| θ3: −0.455 (0.087) | θ3: −0.524 (0.108) | θ3: −0.434 (0.075) | |
| F-test (P-value) | 29.7 (< 0.0001) | 30.5 (< 0.0001) | 31.6 (< 0.0001) |
| tlag = θ4 + θ5dose | θ4: 0.295 | θ4: 0.456 | θ4: 0.249 |
| θ5: 0.0026 (0.0006) | θ5: 0.0043 (0.0013) | θ5: 0.0048 (0.0013) | |
| F-test (P-value) | 14.6 (0.0003) | 10.9 (0.002) | 14.1 (0.0004) |
AAG, Plasma α1-acid glycoprotein (mg dl−1); sex (female = 0, male = 1); dose, rac-methadone dose in mg day−1 (divided by 2 for the methadone enantiomers); θ, regression coefficient.