The combination of carbenicillin disodium and cephalothin sodium was compared in a double-blind study with that of carbenicillin, cephalothin, and gentamicin sulfate therapy in patients with disseminated cancer. These therapies were used empirically prior to recognition of the offending pathogen; however, only infections caused by Gram-negative bacilli were used for the evaluation of the two combinations. A favorable clinical response was observed in 32 (80%) of 40 patients who received carbenicillin and cephalothin and in 31 (76%) of those who received carbenicillin, cephalothin, and gentamicin therapy. The antibacterial activity of the sera of the patients was similar whether the double- or the triple-drug regimen was given. The administration of carbenicillin, cephalothin, and gentamicin was associated with a higher incidence of untoward effects, especially azotemia, than was that of carbenicillin and cephalothin.
Klastersky J, Henri A, Hensgens C, Daneau D. Gram-Negative Infections in CancerStudy of Empiric Therapy Comparing Carbenicillin-Cephalothin With and Without Gentamicin. JAMA. 1974;227(1):45–48. doi:10.1001/jama.1974.03230140019004