A pilot study of the efficacy of constant-infusion ceftazidime in the treatment of endobronchial infections in adults with cystic fibrosis

Study Objective. To compare the efficacy of constant-infusion ceftazidime ( CTZ) with that of traditional intermittent dosing in a pilot trial. Design. Prospective, crossover trial. Subjects. Five adults with cystic fibrosis requiring intravenous antibiotic therapy for pulmonary exacerbations of the disease. Interventions. Patients were initially treated with standard CTZ 2 g 3 time s/day for 10 days. At the next hospitalization patients were crossed over a nd CTZ was administered as a constant infusion at a rate determined to achi eve a serum concentration 6.6 times the minimum inhibitory concentration (M IC) of the least susceptible Pseudomonas aeruginosa isolate. Measurements and Main Results. The pharmacokinetics of CTZ were determined, as were MICs for all P. aeruginosa isolates. Outcome parameters of interes t were changes with therapy in white blood cell count, I! aeruginosa densit y in sputum, and pulmonary function test results. Differences in these para meters for the two forms of administration were not significant. With the e xception of one patient who received 6 g/day with both regimens, the averag e reduction in dosage with the constant infusion was 50%. Conclusion. These preliminary data suggest that constant-infusion CTZ may b e as safe and efficacious as intermittent dosing.