Increase of R-/S-methadone enantiomer concentration ratio in serum of patients treated with either nevirapine or efavirenz.
Author(s): Esteban J, Pellin Mde L, Gimeno C, Barril J, Gimenez J, Mora E, Garcia-Perez AG
Affiliation(s): Instituto de Bioingenieria, Universidad Miguel Hernandez de Elche, Avda. de la Universidad s/n, Elche, Alicante, Spain. jesteban@umh.es
Publication date & source: 2008-12, Drug Metab Lett., 2(4):269-79.
Publication type: Comparative Study; Controlled Clinical Trial; Research Support, Non-U.S. Gov't
An increased methadone enantiomer ratio (R/S) was associated to both nevirapine (179%, n=5) and efavirenz (36%, n=9) treatments when compared with that of controls (n=52). Additionally, in four follow-up patients, both R- and S-methadone normalized concentrations decreased (19%-93%) while R/S increased (22%-314%) following nevirapine/efavirenz treatment. R/S decreased (42%) after non-compliance with efavirenz treatment. Therefore, the methadone-maintenance-treatment outcome should be evaluated when patients are treated with drugs which are supposed to induce CYP3A4 and CYP2B6 isoforms.
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