Use of trimethoprim-sulfamethoxazole singly and in combination with other antibiotics in immunocompromised patients.

Experience with trimethoprim-sulfamethoxazole (TMP-SMZ) alone or in combination with other agents in the treatment of immunocompromised patients other than those with Pneumocystis carinii pneumonitis and the acquired immunodeficiency syndrome is reviewed. A comparative study involving 126 episodes of fever showed a higher rate of response to a TMP-SMZ-carbenicillin regimen than to a gentamicin-carbenicillin combination (85% vs. 69%, respectively, P less than or equal to .04). In another study TMP-SMZ was used after unsuccessful therapy with the combination of an antipseudomonal penicillin and an aminoglycoside; 54% of the 35 patients treated orally and 49% of 86 treated intravenously responded to TMP-SMZ regimens. Other studies document successful results with TMP-SMZ used in combination with either an aminoglycoside or an antipseudomonal penicillin. TMP-SMZ has a role in the treatment of infections due to gram-negative bacilli in immunocompromised hosts, particularly when the infecting agent is not Pseudomonas aeruginosa and is resistant to moxalactam but susceptible to gentamicin.