Current tobramycin regimen
Most decisions regarding antibiotic use are based on expert opinion with few high-quality studies to support what is done. This is reflected by the lack of consensus as a large variability dosing regimens exists between CF centers (7, 20, 21). A regimen of 8-10 mg/kg/day has been shown to achieve peak tobramycin concentrations of 20-30 mg/L (22, 23), a widely accepted PK/pharmacodynamics target in the treatment of APEs. However, this strategy is questioned by our results and some previously reported (9, 24). An average dosage of 7.8 mg/kg/day achieved an average Cmax of 17.9 mg/L in our patients, still within the local target range of 15-25 mg/L, but lower than expected. Higher doses may increase concentration and effectiveness, however, they also increase toxicity (25). Furthermore, the PK of aminoglycosides is altered in patients with CF (26, 27), given the individual variability in the disease itself, CF patients may need a more personalized strategy when it comes to tobramycin dosing.