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

Br J Clin Pharmacol. 1994 Dec;38(6):573-6. doi: 10.1111/j.1365-2125.1994.tb04399.x.


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.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Breath Tests
  • Caffeine / pharmacokinetics*
  • Carbon Dioxide / metabolism
  • Child
  • Child, Preschool
  • Ciprofloxacin / pharmacology*
  • Cystic Fibrosis / enzymology
  • Cystic Fibrosis / metabolism*
  • Cytochrome P-450 CYP1A2
  • Cytochrome P-450 Enzyme System / metabolism
  • Depression, Chemical
  • Female
  • Humans
  • Male
  • Oxidoreductases / metabolism


  • Carbon Dioxide
  • Caffeine
  • Ciprofloxacin
  • Cytochrome P-450 Enzyme System
  • Oxidoreductases
  • Cytochrome P-450 CYP1A2