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 either50 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 eveningover 2 h with a meal. After the end of drinking, at bedtime,in the following morning after waking-up, and on two furtheroccasions during the morning and early afternoon, breath-alcoholtests were performed and samples of urine were collected foranalysis of ethanol and methanol and the 5-hydroxytryptophol(5-HTOL) to 5-hydroxyindol-3-ylacetic acid (5-HIAA) ratio Theparticipants were also asked to quantify the intensity of hangoversymptoms (headache, nausea, anxiety, drowsiness, fatigue, muscleaches, vertigo) on a scale from 0 (no symptoms) to 5 (severesymptoms). The first morning urine void collected 6-11 h afterbedtime as a rule contained measurable amounts of ethanol, being0.09 ± 0.03 g/l (mean ± SD) after 50 g and 0.38± 0.1 g/l after 80 g ethanol. The corresponding breath-alcoholconcentrations were zero, except for three individuals who registered0.01–0.09 g/l. Ethanol was not measurable in urine samplescollected later in the morning and early afternoon. The peakurinary methanol occurred in the first morning void, when themean concentration after 80 g ethanol was {small tilde} 6-foldhigher than pre-drinking values. This compares with a {smalltilde} 50-fold increase for the 5-HTOL/5-HIAA ratio in the firstmorning void. Both methanol and the 5-HTOL/5-HIAA ratio remainedelevated above pre-drinking baseline values in the second andsometimes even the third morning voids. Most subjects experiencedonly mild hangover symptoms after drinking 50 g ethanol (meanscore 2.4 ± 2.6), but the scores were significantly higherafter drinking 80g (78 ± 7.1). The most common symptomswere headache, drowsiness, and fatigue A highly significantcorrelation (r = 0.62–0.75, P <0.01) was found betweenthe presence of headache, nausea, and vertigo and the urinarymethanol concentration in the first and second morning voids,whereas 5-HTOL/5-HIAA correlated with headache and nausea. Theseresults show that analysing urinary methanol and 5-HTOL furnishesa way to disclose recent drinking after alcohol has no longerbeen measurable by conventional breath-alcohol tests for atleast 5–10 h. The results also support the notion thatmethanol may be an important factor in the aetiology of hangover.