Ciprofloxacin pharmacokinetics in patients with cystic fibrosis.

The pharmacokinetics of ciprofloxacin were studied in cystic fibrosis patients and healthy volunteers following oral administration of 500 mg and 1000 mg. Serum kinetics as well as urinary recovery were monitored. As the body weights of cystic fibrosis patients and the healthy volunteers differed significantly, kinetic parameters were calculated on the basis of a constant relative dose in mg/kg body weight. Neither serum kinetics nor urinary recovery differed significantly between the two groups, as indicated by the serum concentration versus time curves ranging from 1.1 to 1.4 mg X h/l, the elimination half-life of 4.4 to 5.1 h and the 24 h urinary recovery which amounted to 35% to 41% of the dose administered. Serum concentrations were linearly proportional to the doses administered. Sputum concentrations were monitored in cystic fibrosis patients. Again, ciprofloxacin sputum levels were linearly proportional to the doses and were within the same range as serum concentrations. Thus, ciprofloxacin kinetics are not altered in cystic fibrosis patients as compared to healthy volunteers.