Parenteral trimethoprim-sulfamethoxazole and carbenicillin as empiric therapy for neutropenic patients with cancer.

A combination of parenteral trimethoprim-sulfamethoxazole and carbenicillin (TMP-SMZ-C) was compared with a gentamicin and carbenicillin combination (G-C) as empiric therapy for the febrile neutropenic patient with cancer in a prospective double-blind trial. Target plasma levels of TMP were achieved easily. When all trials were considered, TMP-SMZ-C was more effective (P less than or equal to 0.045) than G-C. When only proven infections were considered, the two regimens were equally effective. Adverse effects of both regimens were similar. Experience with infections due to individual organisms, particularly Pseudomonas aeruginosa and Staphylococcus aureus, was limited. General recommendations for use of TMP-SMZ-C in this patient population cannot be made until more comprehensive studies are done.