Table 5.
Summary of Margin of Safety (MOS) values for R- and S-methadone for the Caucasian and Chinese population
| Enantiomer | Stage dosing | Effective dose (rac-methadone mg/day) | Toxic dosea | Margin of Safety (MOS)b | ||
|---|---|---|---|---|---|---|
| (enantiomer mg/day) | ||||||
| Caucasian | Chinese | Caucasian | Chinese | |||
| R-methadone | Initial | 10 | 32.4 | 15.8 | 3.2 | 1.6 |
| Maintenance | 60 | 32.4 | 15.8 | 0.5 | 0.3 | |
| S-methadone | Initial | 10 | 5.5 | 1.9 | 0.6 | 0.2 |
| Maintenance | 60 | 5.5 | 1.9 | 0.09 | 0.03 | |
The MOS is defined as the ratio between the predicted BMDL10 of the enantiomers for the sensitive population (99th percentile of the Cmax in the heart venous blood) and the therapeutic dose of rac-methadone
aBMDL10 values for the sensitive population (99th percentile of Cmax in heart venous blood) were used as toxic dose for 1% population (TD1)
bObtained by dividing TD1 by effective dose