Excretion of alcohol in urine and diuresis in healthy men in relation to their age, the dose administered and the time after drinking

Healthy male volunteers drank neat whisky in amounts corresponding to 0.51, 0.68, or 0.85 g ethanol/kg body weight in 15-25 min after an overnight (10 h) fast. Urine was collected immediately before drinking and then at 60 min intervals for 7-8 h after intake. The volumes of urine voided were measured and the concentrations of alcohol (UAC) were determined by an enzymatic method. Ethanol-induced diuresis showed large inter-subject variations. The flow of urine was maximum between 60 and 120 min post-drinking when the median rates of production were 117 ml/h (range 55-335), 113 ml/h (range 41-453) and 373 ml/h (range 215-485) for 0.51, 0.68, and 0.85 g ethanol/kg respectively. The output of urine returned to normal (30-60 ml/h) after the peak UAC had passed despite an elevated blood alcohol concentration (BAC). The average amount of alcohol excreted in urine was 0.29 g (S.D. 0.119), 0.44 g (S.D. 0.246), and 1.00 g (S.D. 0.427) after the consumption of 0.51, 0.68 and 0.85 g ethanol/kg respectively. Neither peak diuresis nor the amount of alcohol excreted depended on a subject's age between 20 and 60 years. This work shows that after drinking a moderate dose of alcohol, only 0.7-1.5% of the amount consumed is excreted unchanged in urine. Ethanol-induced diuresis is most pronounced for the first 1-2 h after drinking (rising BAC). The production of urine returns to normal during the post-absorptive state.