Review
Copyright ©The Author(s) 2016.
World J Gastroenterol. Jan 21, 2016; 22(3): 1260-1278
Published online Jan 21, 2016. doi: 10.3748/wjg.v22.i3.1260
Figure 1
Figure 1 Metabolic pathways of theophylline. Numbers in parentheses indicate percentages of urinary metabolites in adult humans. Theophylline is hydroxylated at the C8 position to form 1,3-dimethyluric acid and demethylated at the N1 and N3 positions, to yield 3-methylxanthine and 1-methylxanthine, respectively. The latter undergoes subsequent oxidation, by xanthine oxidase, to 1-methyluric acid. CYP1A2 is responsible for about 80% of theophylline metabolism[30].