title: Time course and reproducibility of urinary excretion profiles of ethanol, methanol, and the ratio of serotonin metabolites after intravenous infusion of ethanol.
abstract: BACKGROUND
  The aim of this study was to determine the time course and reproducibility of urinary excretion profiles of ethanol, methanol, and ratio of serotonin metabolites, 5-hydroxytryptophol (5HTOL) to 5-hydroxyindoleacetic acid (5HIAA), under strictly controlled conditions.
  
  
  METHODS
  Nine healthy volunteers (6 women and 3 men) received 0.40 g of ethanol/kg of body weight on two occasions by constant rate intravenous infusion 30 min. Urine was voided before administration of ethanol and thereafter every 60 min for a total of 8 hr. Concentrations of ethanol and methanol in urine were determined by headspace gas chromatography, and the serotonin metabolites 5HTOL and 5HIAA were measured by gas chromatography-mass spectrometry and high-performance liquid chromatography, respectively.
  
  
  RESULTS
  The peak concentration of ethanol in urine occurred at 30 or 60 min after the infusion ended. The peak concentration of methanol and the 5HTOL/5HIAA ratio developed more gradually, reaching a plateau at 213 to 220 min and 200 to 220 min postinfusion, respectively. The concentration-time profiles of ethanol and the 5HTOL/5HIAA ratio varied more between subjects than within subjects (p < 0.001), whereas the inter- and intraindividual variation in the pharmacokinetics of methanol were not significantly different (p > 0.05). The concentration of methanol and the 5HTOL/5HIAA ratio remained above the endogenous levels at 8-hr postinfusion despite the fact that urinary ethanol was no longer measurable (<0.01 g/liter) after 5 to 6 hr.
  
  
  CONCLUSIONS
  Measuring the concentrations of methanol and the ratio of serotonin metabolites (5HTOL/5HIAA) in urine is a more sensitive way to monitor recent drinking, compared with analysis of ethanol in body fluids. Moreover, the concentration-time profiles of methanol and the 5HTOL/5HIAA ratio showed a good test-retest stability. The present intravenous infusion experiment confirms previous work on these markers when ethanol was given perorally. The urinary methanol and the 5HTOL/5HIAA ratio have applications in forensic and clinical medicine as indicators of acute alcohol consumption.
authors.affiliation: Department of Forensic Toxicology, University Hospital, Linköping, Sweden. wayne.jones@rmv.se
authors.forename: A W
authors.initials: AW
authors.lastname: Jones
authors.forename: A
authors.initials: A
authors.lastname: Helander
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D002492:Central Nervous System Depressants / Q000494:pharmacology / Q000652:urine*; D000431:Ethanol / Q000494:pharmacology / Q000652:urine*; D005260:Female; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine*; D008297:Male; D000432:Methanol / Q000652:urine*; D015203:Reproducibility of Results; D012701:Serotonin / Q000378:metabolism*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D002492:Central Nervous System Depressants; D012701:Serotonin; D000431:Ethanol; D006897:Hydroxyindoleacetic Acid; D000432:Methanol