Long-term tobramycin aerosol therapy of chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis.

Fourteen cystic fibrosis patients (aged 9 to 20 years), chronically infected with Pseudomonas aeruginosa (PA), inhaled 80 mg (2 ml) tobramycin twice daily, because a significant clinical deterioration had occurred. Mean duration of aerosol therapy was 20.3 months (range, 11 to 38 months). There were no toxic side effects and no significant systemic absorption, 50 of 70 tobramycin serum levels being below the minimal detectable value of 0.1 mg/l. After 12 months of therapy there was an improvement of lung function, Po2, and weight. The frequency of intravenous therapy was reduced. Tobramycin resistance occurred in 5.8% of all PA strains after 10 to 29 months and did not represent a clinical problem. In a few patients PA was eradicated from sputum.