The use of plasma levels to optimize methadone maintenance treatment

Therapeutic Drug Monitoring for Methadone: Scanning the Horizon

“…However, few have related the problem of dosage scheduling to this more immediately relevant variable [62,63]. In the past, most believed that the problem of dosage scheduling could not be related to plasma methadone concentration [64,65].…”

“…Poor or insufficient compliance is of considerable importance for the relationship between plasma concentration and methadone dose. When compliance is good, the relationship between plasma concentration and methadone dose is highly correlated [61,63] and plasma methadone concentrations can be used effectively to validate dosing regimes, as well as to assess compliance.…”

Variability of Plasma Methadone Concentration in Opiate Dependent Receiving Methadone: A Personalised Approach Towards Optimizing Dose

“…Accordingly, several pharmacokinetic studies have been carried out to investigate whether therapeutic drug monitoring (TDM) is effective as a clinical endpoint, on the one hand, and to study the methadone kinetic profile, on the other. There has been suggestive evidence to nonfrequently monitor the kinetic of methadone to explain some unpredicted clinical response (Loimer and Schmid, 1992;Schmidt et al, 1993;Wolff and Hay, 1994;de Vos et al, 1996). It may be useful especially when all other measures have been taken adequately and a patient still cannot hold on methadone with high doses.…”

Letter to the Editor: On the Usefulness of Therapeutic Drug Monitoring of Methadone

“…This large variability of methadone concentrations has prompted several authors to examine whether a minimum methadone blood level can reliably support effective methadone maintenance therapy [17,[27][28][29][30][31][32][33]. In some studies, such a threshold was not found [31][32][33], while various values, ranging from 50 to 600 ng/ml, were found in other studies [17,27,29,30,34,35].…”

“…In some studies, such a threshold was not found [31][32][33], while various values, ranging from 50 to 600 ng/ml, were found in other studies [17,27,29,30,34,35]. A concentration of 400 ng/ml for (R,S)-methadone is now often considered as necessary to provide stabilized maintenance [36,37] and is used as a reference value when performing therapeutic drug monitoring of methadone.…”