Tobramycin Pharmacokinetics in Pediatric Patients With Primary Ciliary Dyskinesia

Patients with primary ciliary dyskinesia (PCD) are commonly treated for pulmonary exacerbations with intravenous tobramycin, but data on tobramycin pharmacokinetics in PCD is lacking. The objective of this study was to compare tobramycin pharmacokinetics in pediatric patients with PCD to those with cystic fibrosis (CF).

This retrospective study included pediatric patients hospitalized for a pulmonary exacerbation between January 2018 and June 2023. Included patients were treated with systemic tobramycin and had two concentrations usable to calculate patient-specific pharmacokinetics. Each patient with PCD was matched 1:2 to patients with CF based on age. The primary outcome was tobramycin elimination rate constant.

Seven patients with PCD were matched to 14 patients with CF. Baseline characteristics were similar between groups. The final tobramycin dose was not significantly different between groups (9.3 vs. 11.8 mg/kg, p = 0.192). All doses were infused over 30 min every 24 h. Tobramycin elimination rate constant (0.510 vs. 0.493 h^-1, p = 0.433) and volume of distribution (0.31 vs. 0.23 L/kg, p = 0.640) were not different between groups. No patient experienced acute kidney injury. Additionally, both groups experienced similar duration of tobramycin therapy (12.3 vs. 9.6 days, p = 0.184) and length of stay (12.0 vs. 12.6 days, p = 0.801).

No difference in tobramycin elimination rate constant was found between patients with PCD and those with CF. Clinical outcomes were not significantly different between groups. Although not statistically significant, a lower tobramycin dose was observed in patients with PCD.