Bronchial response to nebulized antibiotics in children with cystic fibrosis

Nebulized antibiotics are being used increasingly in children with cystic fibrosis. We assessed the effect of nebulized antibiotic solutions of varying tonicity on lung function in 12 children aged 5-15 yrs with cystic fibrosis. Baseline forced expiratory volume in one second and (FEV1) was measured, followed by a single nebulization of normal saline (272 mosmol.kg-1), tobramycin (248 mosmol.kg-1), or ticarcillin (3,080 mosmol.kg-1). All children received each of these, administered randomly, one per day. FEV1 was remeasured 5, 15 and 30 min after completion of the nebulization. Ticarcillin (mean fall 10.7% (SD 8.9)) caused a larger fall in FEV1 than normal saline (4.8% (4.3), p less than 0.05). The fall in FEV1 for ticarcillin was greater than for tobramycin (1.2% (2.0), p less than 0.05). Normal saline did not result in a significantly larger fall in FEV1 than tobramycin (p greater than 0.05). Bronchoconstriction to ticarcillin persisted at 30 min. We conclude that nebulized antibiotics can affect lung function in children with cystic fibrosis if the solutions are hypertonic.