Dosing implications of altered gentamicin disposition in patients with cystic fibrosis

Area of Science:

• Pharmacology
• Pediatrics
• Pulmonology

Background:

• Gentamicin is an antibiotic commonly used to treat bacterial infections.
• Cystic fibrosis (CF) affects multiple organs, including the lungs, leading to altered drug pharmacokinetics.
• Standard dosing guidelines for gentamicin may not be appropriate for patients with CF.

Purpose of the Study:

• To investigate the pharmacokinetic approach for gentamicin dosing in pediatric and young adult patients with cystic fibrosis.
• To compare gentamicin pharmacokinetics in patients with CF to those without the disease.
• To determine the need for individualized gentamicin therapy in CF patients.

Main Methods:

• A one-compartment open-model analysis was used to study steady-state gentamicin pharmacokinetics.
• Nineteen children and young adults with cystic fibrosis were included in the study.
• Pharmacokinetic parameters were compared to a control population of children without CF.

Main Results:

• Patients with CF exhibited a significantly larger apparent volume of distribution and total plasma clearance for gentamicin.
• Higher daily gentamicin doses were required in CF patients to achieve similar steady-state levels.
• No significant differences in elimination rate constant or half-life were observed between the groups.
• Correlations between renal function/body weight and pharmacokinetic parameters found in healthy children were not observed in CF patients.

Conclusions:

• Altered gentamicin disposition in cystic fibrosis necessitates individualized dosing strategies.
• Current gentamicin dosing nomograms derived from normal populations are not suitable for CF patients.
• A pharmacokinetic approach is crucial for optimizing gentamicin therapy in individuals with CF.