Audit of once-daily dosing gentamicin therapy in neutropenic fever

During a 12-month study, 42 adult patients with febrile neutropenia (granulocytes < 1 x 10(9)/l) were treated with once-daily gentamicin (5 mg/kg). Serum gentamicin trough levels were measured 24 hours after the first dose, then twice weekly if < 1 mg/l. Gentamicin was halved if the trough level was 1-2 mg/l and usually stopped if > 2 mg/l. One hundred and sixty samples were assayed: 122 (76%) < 1 mg/l, 27 (17%) l-2 mg/l and 11 (7%) > 2 mg/l. All 1-2 mg/l samples and three of the > 2 mg/l samples (taken at the wrong time) reverted to <1 mg/l with dosage adjustment. The protocol proved simple and effective with a low incidence of gentamicin-associated nephrotoxicity (7%) and no sepsis-related deaths.