URINARY-EXCRETION OF METHANOL AND 5-HYDROXYTRYPTOPHOL AS BIOCHEMICAL MARKERS OF RECENT DRINKING IN THE HANGOVER STATE

Twenty healthy social drinkers (9 women and 11 men) drank either 50 g of ethanol (mean intake 0.75 g/kg) or 80 g (mean 1.07 g/kg) according to choice as white wine or export beer in the evening over 2 h with a meal. After the end of drinking, at bedtime, in the following morning after waking-up, and on two further occasions during the morning and e arly afternoon, breath-alcohol tests were performed and samples of uri ne were collected for analysis of ethanol and methanol and the 5-hydro xytryptophol (5-HTOL) to 5-hydroxyindol-3-ylacetic acid (5-HIAA) ratio . The participants were also asked to quantify the intensity of hangov er symptoms (headache, nausea, anxiety, drowsiness, fatigue, muscle ac hes, vertigo) on a scale from 0 (no symptoms) to 5 (severe symptoms). The first morning urine void collected 6-11 h after bedtime as a rule contained measurable amounts of ethanol, being 0.09 +/- 0.03 g/l (mean +/- SD) after 50 g and 0.38 +/- 0.1 g/l after 80 g ethanol. The corre sponding breath-alcohol concentrations were zero, except for three ind ividuals who registered 0.01-0.09 g/l. Ethanol was nor measurable in u rine samples collected later in the morning and early afternoon. The p eak urinary methanol occurred in the first morning void, when the: mea n concentration after 80 g ethanol was similar to 6-fold higher than p re-drinking values. This compares with a similar to 50-fold increase f or the 5-HTOL/5-HIAA ratio in the first morning void. Both methanol an d the 5-HTOL/5-HIAA ratio remained elevated above pre-drinking baselin e values in the second and sometimes even the third morning voids. Mos t subjects experienced only mild hangover symptoms after drinking 50 g ethanol (mean score 2.4 +/- 2.6), but the scores were significantly h igher after drinking 80 g (7.8 +/- 7.1). The most common symptoms were headache, drowsiness, and fatigue. A highly significant correlation ( r = 0.62-0.75, P < 0.01) was found between the presence of headache, n ausea, and vertigo and the urinary methanol concentration in the first and second morning voids, whereas 5-HTOL/5-HIAA correlated with heada che and nausea. These results show that analysing urinary methanol and 5-HTOL furnishes a way to disclose recent drinking after alcohol has no longer been measurable by conventional breath-alcohol tests for at least 5-10 h. The results also support the notion that methanol may be an important factor in the aetiology of hangover.