Comparison of the efficacy and safety of amikacin once or twice-a-day in the treatment of severe gram-negative infections in the elderly.

The aim of this study was to compare the efficacy and safety of amikacin given either as single injection or as two injections within 12-h interval in the treatment of severe gram-negative infections in elderly patients. Thirty-nine non-selected consecutive patients of a general internal medicine facility were randomized to receive the same total daily dose of amikacin either as a single dose (19 patients) or divided into two doses injected at 12-h interval (20 patients). Amikacin was used alone or in combination with metronidazole, clindamycin, fosfomycin or a beta-lactam. Clinical and bacteriological responses were satisfactory and comparable in the two groups. There was no difference between the once/day and the twice-a-day groups with respect to drug dosage, duration of therapy and concomitant treatment. Only one patient (BID group) showed a rise of serum creatinine during the observation period. Amikacin alone or in combination can be regarded as an efficacious and safe antibiotic in the treatment of severe gram-negative infections in elderly patients, whether the daily dose is administered in a single infusion or in a BID interval.