title: [Pilot study of the metabolism of codeine to morphine and a possible modification by benzodiazepines].
abstract: After administration of high-dose codeine we found that in two cases 20-40% of the total morphine-equivalents in the 24-hour urine sample were free morphine. After another 24 hours the proportion of free morphine was up to 70% and after roughly 96 hours even went up to 96%. Although 10% of the administered codeine was eliminated as morphine. In contrast to the values reported in literature we found that even with codeine/morphine ratios greater than 0.5 and morphine concentrations of up to 2000 ng/ml urine one cannot naturally conclude that morphine/diamorphine has been consumed. The short half-life of codeine in serum was 2-4 hours, the final half-life was 9-11 hours. In urine we found a short half-life of 1-6 hours as well as a long half-life of 7-12 hours. When diazepam was administered simultaneously with codeine the expected half-life in serum was up to 1.5 times and in urine 2.5 times. The codeine/morphine ratios were hardly affected so far as evidence goes which they give of preceding drug-intake.
authors.affiliation: Institut für Rechtsmedizin, Universität Freiburg/Br.
authors.forename: G
authors.initials: G
authors.lastname: Friedrich
authors.forename: B
authors.initials: B
authors.lastname: Allgaier
authors.forename: T
authors.initials: T
authors.lastname: Schneider
authors.forename: G
authors.initials: G
authors.lastname: Schwarzkopf
mesh_terms: D001711:Biotransformation / Q000187:drug effects; D003061:Codeine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D003975:Diazepam / Q000494:pharmacology*; D006801:Humans; D008657:Metabolic Clearance Rate / Q000187:drug effects; D009020:Morphine / Q000494:pharmacology*
chemical_list: D009020:Morphine; D003975:Diazepam; D003061:Codeine
vernacular_title: Pilotstudie zur Metabolisierung von Codein zu Morphin und eine mögliche Beeinflussung durch Benzodiazepine.