Disposition of caffeine and its metabolites in man
The disposition of caffeine and its metabolites was studied in six healthy subjects by use of sensitive and specific assays. The primary degradation of caffeine in man was found to be N-demethylation and/or ring oxidation to theophylline, paraxanthine, theobromine and 1,3,7-trimethyluric acid. These...
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Published in | The Journal of pharmacology and experimental therapeutics Vol. 224; no. 1; pp. 180 - 185 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
United States
American Society for Pharmacology and Experimental Therapeutics
01.01.1983
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Subjects | |
Online Access | Get full text |
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Summary: | The disposition of caffeine and its metabolites was studied in six healthy subjects by use of sensitive and specific assays.
The primary degradation of caffeine in man was found to be N-demethylation and/or ring oxidation to theophylline, paraxanthine,
theobromine and 1,3,7-trimethyluric acid. These compounds were further degraded to dimethylated uric acids, monomethylxanthines
and monomethyluric acids. About 3 and 6% of the drug was converted to theophylline and theobromine, respectively. The elimination
of paraxanthine after its formation did not follow linear kinetics. A large urine recovery of 1-methylxanthine after caffeine
administration in comparison with the amount recovered after administration of theophylline suggests an inhibitory effect
on the degradation of this metabolite by either caffeine itself or another metabolite of caffeine. Caffeine and its primary
metabolites, dimethylxanthines, were extensively reabsorbed in the renal tubule. Their renal clearances were highly urine
flow-dependent and their urinary excretion varied with urine output during the study. About 70% of the dose was recovered
in the urine. Postulated degradation pathways of caffeine are discussed. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0022-3565 1521-0103 |