Metabolism of isometheptene in human urine and analysis by gas chromatography-mass spectrometry in doping control.

A study of the metabolism of isometheptene, an antispasmodic drug, in man and comparison with heptaminol metabolism, is presented in this paper. Isometheptene and two metabolites were detected in human urine after oral administration of a tablet containing isometheptene mucate. The urine level of the parent drug, which is excreted during the first 24 h, was determined using gas chromatography-mass spectrometry, after alkaline extraction with organic solvent. A minor metabolite of isometheptene was converted to heptaminol in vitro under the acidic hydrolysis conditions used for the screening procedure of stimulants and narcotics in doping control analysis.