Intravenous sulfamethoxazole and trimethoprim for serious gram-negative bacillary infection.

Intravenous therapy with sulfamethoxazole and trimethoprim cured seven patients with serious gram-negative infection. Three patients had bacteremia, three had pneumonia, and one each had meningitis, peritonitis, pyogenic liver abscesses, and urinary tract infection. Sulfamethoxazole and trimethoprim was selected in three patients with renal failure to avoid aminoglycoside-induced nephrotoxicity, in three patients because of penicillin allergy, and in two cases because of bacterial resistance to other readily available antibiotics. Adverse drug reactions occurred in three cases and included oral monilia, transient leukopenia, and fluid overload. In contrast to the new broad-spectrum cephalosporin antibiotics, sulfamethoxazole and trimethoprim costs two to 2 1/2 times less and has not been associated with the emergence of bacterial resistance during therapy. This may favor the use of parenteral sulfamethoxazole and trimethoprim for some patients with serious gram-negative infection.