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.