National survey of extended-interval aminoglycoside dosing in pediatric cystic fibrosis pulmonary exacerbations

Objectives: The Cystic Fibrosis Foundation recently deemed the use of extended-interval dosing (EID) of aminoglycosides acceptable for the treatment of cystic fibrosis (CF) pulmonary exacerbations, but current practices across United States (US) pediatric CF accredited care centers and affiliate programs are unknown. The objectives of this research are to characterize the practice trends, dosing strategies, therapeutic drug monitoring practices, and adverse drug reaction monitoring of EID of aminoglycosides in the treatment of pulmonary exacerbations across US pediatric CF programs.

Methods: A 38-question online survey was distributed on behalf of the author by the CF Foundation to all US pediatric CF accredited care centers and affiliate programs.

Results: Of the 70 participating CF programs (42.2% survey response rate), 94.3% reported using EID of aminoglycosides (as once-daily or twice-daily dosing), whereas 84.3% reported using once-daily EID in their pediatric CF population. The frequency of EID use increased with patient age. Tobramycin dosed 10 mg/kg per day every 24 hours, infused over the course of 30 minutes, in combination with an antipseudomonal beta-lactam, was the most commonly cited regimen. Monitoring of aminoglycoside serum concentrations was reported by 98.5% of programs, with a tobramycin peak of 25 to 30 mg/L and trough of less than 1 mg/L targeted most frequently. Nephrotoxicity was commonly monitored through serum creatinine measurements, whereas ototoxicity was monitored by audiometry in approximately one-half of programs.

Conclusions: This study indicates that the use of EID of aminoglycosides across US pediatric CF accredited care centers and affiliate programs is common, particularly among adolescents, with tobramycin being the preferred agent.