Aminoglycoside treatment I. Administration of gentamicin once versus three times daily

: Gentamicin is the most commonly used aminoglycoside in Danish hospitals. The aim of this study was to compare two dosage regimens, thrice-a-day (TID) and once-a-day (OD) with regard to efficacy, safety and tissue toxicity. Twenty-three patients were allocated to TID and 26 were allocated to OD gentamicin. Data from patients treated for more than 72 hours were evaluated. Efficacy was assessed by the rate at which body temperature fell to normal. Renal toxicity was judged by an increase in serum creatinine of more than 50 mumol/l and inner ear toxicity was clinically estimated daily during treatment, followed up by audiometry if positive signs occurred. Serum gentamicin was determined daily to estimate the size of next dose. A low frequency of dose adjustments was considered to reflect safety, as well as the absence of renal and inner ear affection. Results showed no significant differences between the two groups regarding efficacy, safety or tissue toxicity. Renal toxicity developed in two patients on TID regime and in one patient on OD regime. No inner ear toxicity was seen. The renal toxicity appeared unpredictably, both early and late in the treatment period and preceded by low or high values serum gentamicin. It is recommended that gentamicin be administered OD for reasons of economy and convenience and that kidney function be monitored daily throughout the treatment period.