A randomized study of tobramycin plus ticarcillin, tobramycin plus cephalothin and ticarcillin, or tobramycin plus mezlocillin in the treatment of infection in neutropenic patients with malignancies.

Two hundred twenty-five patients with 358 febrile episodes were treated with tobramycin and ticarcillin (TT), tobramycin and mezlocillin (TM), or tobramycin, ticarcillin and cephalothin (TTC). There were no statistically significant differences in the response rates for patients who were proven to have infection (67% with TT, 69% with TTC and 53% with TM). Patients were more often cured of their infection if their neutrophil count rose during therapy. In this study, the addition of cephalothin to TT did not increase the frequency of azotemia (10% and 12%, respectively). Although mezlocillin has a broader spectrum of activity in vitro than ticarcillin, it was not more efficacious when combined with tobramycin than ticarcillin plus tobramycin for the treatment of infections in neutropenic patients.