Effect of age and sex on the N-demethylation rate of 14C-aminopyrine, studied by the breath test.

The effect of age and sex on the N-demethylation rate of 14C-aminopyrine was studied by breath test in 28 normal subjects (12 men, 16 women) aged 26 to 86. It was found that demethylation of aminopyrine was inversely related with age and unaffected by sex. 6 out of 8 patients aged 70 or over, had breath test values within the range of values obtained in 31 patients with alcoholic cirrhosis. In the elderly, a breath test can therefore be considered abnormal only if it is compared with a control group of the same age.