PK samples
CF patients received 7.5mg/kg of IV tobramycin every 24 hours for 14 days in their antibiotic regimen for treatment of an APE. Pharmacists adjusted the dose per standard practice with target peak of 15-25 mg/L and trough of less than 0.5 mg/L. In case of treatment failure, clinicians were free to make any modifications to the antibiotic regimen including dosing changes, extending the duration of treatment or changing any of the antibiotics. Tobramycin peaks and troughs (1 hour after and 30 minutes before administration respectively) were measured at Day3. Concentrations were determined with an automated and validated immunoenzyme method on an AU5800 chemistry analyzer (Beckman Coulter, Brea, CA). The linear range for this assay was 0.5-50.0 mg/L with the intraday and interday variability being lower than 10%.