title: Plasma methadone concentrations as an indicator of opioid withdrawal symptoms and heroin use in a methadone maintenance program.
abstract: Plasma methadone concentrations and its main metabolite D,L-2-ethylidiene-1,5-dimethyl-3,5-diphenylpyrrolidine (EDDP) were determined in 93 patients under methadone maintenance treatment to assess their relationship with heroin use and opioid withdrawal symptoms. Neither plasma concentrations of methadone nor EDDP were significantly different when patients that used heroin in last 3 months were compared with those testing negative for this drug (methadone, 355 +/- 217 versus 369 +/- 216 ng/ml, t = 0.29, P = NS; EDDP, 49 +/- 28 versus 54 +/- 40 ng/ml, t = 0.51, P = NS). No correlation between opioid withdrawal scale scores and plasma concentrations of methadone (r = 0.02, P = NS) and EDDP (r = -0.14, P = NS) was found. Therapeutic drug monitoring during methadone maintenance seems to be useful for assessing compliance with treatment but not for predicting heroin use and subjective withdrawal symptoms.
authors.affiliation: Servei de Psiquiatria, Hospital del Mar, Universitat Autònoma de Barcelona, Spain. mtorrens@imim.es
authors.forename: M
authors.initials: M
authors.lastname: Torrens
authors.forename: C
authors.initials: C
authors.lastname: Castillo
authors.forename: L
authors.initials: L
authors.lastname: San
authors.forename: E
authors.initials: E
authors.lastname: del Moral
authors.forename: M L
authors.initials: ML
authors.lastname: González
authors.forename: R
authors.initials: R
authors.lastname: de la Torre
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D006556:Heroin Dependence / Q000097:blood / Q000175:diagnosis / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008875:Middle Aged; D009460:Neurologic Examination / Q000187:drug effects; D012680:Sensitivity and Specificity; D013030:Spain; D015813:Substance Abuse Detection; D013375:Substance Withdrawal Syndrome / Q000097:blood / Q000175:diagnosis*; D016312:Treatment Refusal
chemical_list: D008691:Methadone