Inhibition of caffeine metabolism by ciprofloxacin in children with cystic fibrosis as measured by the caffeine breath test.

Abstract

The caffeine breath test was carried out in six children with cystic fibrosis, before and during a course of ciprofloxacin. There was a significant decrease in the 2 h cumulative labelled CO2 exhaled during ciprofloxacin treatment, mean difference (s.d.) ‐5.2(3.3)%, P < 0.02. The results suggest an inhibition of 3‐N‐demethylation of caffeine (CYP1A2 enzyme activity) by ciprofloxacin. Ciprofloxacin may cause significant drug interactions in children with cystic fibrosis. The caffeine breath test can be used to study drug interactions involving CYP1A2 in children. 1994 The British Pharmacological Society