A prospective study of gentamicin and netilmicin in the treatment of pyelonephritis

Gentamicin and netilmicin were evaluated in a prospective randomized study of pyelonephritis in adults. Sixteen patients initially received a standard gentamicin dosage of 1.5 mg/kg every eight hours, and thirteen patients received a reduced netilmicin dosage of 2 mg/kg every twelve hours. Antibiotic dosages were adjusted to maintain a peak serum concentration of 4 to 8 μg/ml. Escherichia coli was the most common infecting organism and nineteen of 24 patients tested had antibody-coated bacteria in their urine. A clinical response to therapy occurred in all patients in both groups within 48 hours; a bacteriologic cure was achieved in twelve of thirteen patients treated with netilmicin and thirteen of sixteen patients with gentamicin. One superinfection occurred in the netilmicin group, and two relapses and one persistence of infection occurred in the gentamicin group. A transient impairment of renal function was observed in two of sixteen gentamicin-treated patients and in one of thirteen netilmicin-treated patients. No ototoxicity was observed. An elevation in serum alkaline phosphatase was noted in four of thirteen netilmicin patients and in two of sixteen gentamicin patients (p>0.1). In this study, netilmicin was as effective as gentamicin in the treatment of pyelonephritis in adults.