Gentamicin pharmacokinetics during continuous venovenous hemofiltration in critically ill septic patients

Objective: Current dosing recommendations for administration of gentamicin to septic patients with acute kidney injury (AKI) on continuous venovenous hemofiltration (CVVH) at a filtration rate of 45 ml/kg/h are missing. Aim: To describe gentamicin pharmacokinetics and to find an optimal dosing regimen in patients on CVVH. Methods: Seven adult patients were included. Patients received loading dose of 240 mg followed by application of maintenance dose every 24 hours. Maintenance dose was adjusted according to gentamicin C-max/MIC ratio and drug levels simulation using a pharmacokinetic programme. Results: Median total clearance (0.59-0.79 ml/min/kg) was similar to patients with normal renal function; median volume of distribution was higher than observed in non-septic patients (about 0.5 l/kg versus 0.25 l/kg). Patients with diuresis required an increase of gentamicin dose to reach C-max/MIC ratio. Conclusion: Septic patients with AKI on CVVH (45 ml/kg/h) require a loading dose of 240 mg, followed by therapeutic drug monitoring to optimize maintenance dose.