A W Jones1, A Helander. 1. Department of Forensic Toxicology, University Hospital, Linköping, Sweden. wayne.jones@rmv.se
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.
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.