Single daily doses of tobramycin in therapy of urinary tract infections.

Results of therapy with tobramycin for infections caused by susceptible pathogens have been impressive. The usual multiple dose regimen is aimed at maintenance of the serum concentration of tobramycin above the minimal inhibitory concentration of the causative pathogen throughout the course of therapy. Evidence is accumulating, however, that the urinary concentration of antibiotics may be of greater importance than the serum concentration in the treatment of urinary tract infections. This concept has been supported by results of studies with nitrofurantoin, naladixic acid, tetracycline, and, more recently, gentamicin. The present study of 90 patients with urinary tract infections treated with a single intramuscular daily dose of tobramycin resulted in round-the-clock urinary levels of tobramycin that exceeded the minimal inhibitory concentration of the offending pathogen. The clinical and bacteriologic response to therapy was excellent, and no oto- or nephrotoxicity occurred. This regimen frequently allows for therapy on an outpatient basis, fewer painful injections for the patient, and the saving of nursing time and expensive supplies.