The use of 5-hydroxytryptophol as an alcohol intake marker.

5-Hydroxytryptophol (5HTOL) occurs naturally in animals as a metabolite of serotonin. Ethanol interacts with serotonin metabolism to increase the production of 5HTOL at the expense of 5-hydroxyindoleacetic acid (5HIAA). This can be used clinically in the treatment of alcohol dependence to improve the detection of relapse in alcohol drinking, by monitoring daily the urinary 5HTOL/5HIAA ratio. In one experiment the sensitivity of this marker in detecting alcohol drinking the previous day was more than 10-fold greater than measuring urinary ethanol. Genetic polymorphism in alcohol and aldehyde dehydrogenases, which is known to influence the ethanol metabolism, does not confound the clinical use of 5HTOL as a marker. Disulfiram and cyanamide, however, will elevate urinary 5HTOL/5HIAA ratio.