Pharmacokinetics of ticarcillin in patients with cystic fibrosis: a controlled prospective study

We compared the pharmacokinetics of ticarcillin at a dose of 120 mg/kg in 11 patients with cystic fibrosis to 11 control subjects matched for age and sex. The mean elimination half-life of ticarcillin in serum was 70.8 minutes in the control subjects and 53.1 minutes in the patients with cystic fibrosis. The total body clearance of ticarcillin was significantly higher in cystic fibrosis patients (65.6 +/- 22.0 versus 46.2 +/- 10.9 ml/min/m2 in control subjects; p = 0.017). The nonrenal clearance of ticarcillin was also significantly higher in patients with cystic fibrosis (24.8 +/- 11.1 versus 13.3 +/- 6.0 ml/min/m2 for the control group; p = 0.006). There was no significant difference in volume of distribution between the two groups. We concluded that the shorter elimination half-life and the higher total body clearance of ticarcillin in patients with cystic fibrosis are a result of an increase in both renal and nonrenal elimination.