Comparative clinical study of tobramycin and gentamicin.

Gentamicin and tobramycin have been compared in vitro and as single-drug therapy in patients with a serious infection caused by gram-negative rods. In vitro, a slight advantage of tobramycin over gentamicin has been found against Pseudomonas aeruginosa. Cross-resistance between gentamicin and tobramycin has been observed for gentamicin-resistant strains of P. aeruginosa and Providence but was not always present. The clinical effectiveness of gentamicin and tobramycin was similar: 14 (45.1%) out of the 31 patients in each series responded favorably. The clinical results were much better in urinary tract infections (66% of favorable responses) than in wound infections, pulmonary infections, septicemia, and meningitis (26% of favorable responses). The frequency of adverse reactions encountered in the present series was similar for both drugs.