Letters to the Editor
January 1998

High Interindividual Variability of Methadone Enantiomer Blood Levels to Dose Ratios

Author Affiliations

Copyright 1998 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.1998

Arch Gen Psychiatry. 1998;55(1):89-90. doi:

Methadone is used as a maintenance treatment for opiate addiction. A linear relationship with a good correlation coefficient (n=31, r=0.82, P<.001) has been calculated between methadone dose and methadone concentrations in plasma.1 Methadone is marketed as a mixture (50:50) of 2 enantiomers called (R)-methadone and (S)-methadone, but (R)-methadone accounts for nearly all of the opioid effects of racemic methadone.2 We have developed a stereospecific analytical method that allows measurement of the concentrations of (R)-methadone and (S)-methadone.3 It was used to determine the (R)-methadone and (S)-methadone trough concentrations in the serum or plasma samples from 50 addicts receiving racemic methadone therapy in steady-state conditions.

First Page Preview View Large
First page PDF preview
First page PDF preview