Use of trimethoprim-sulfamethoxazole in a glucose-6-phosphate dehydrogenase-deficient population

Trimethoprim-sulfamethoxazole (TMP-SMZ) has been associated with hemolytic anemia in patients deficient in glucose-6-phosphate dehydrogenase (G-6-PD). The effect of a daily dose of SMZ of 50 mg/kg was evaluated in a double-blinded study that compared vancomycin with TMP-SMZ given intravenously for treatment of serious Staphylococcus aureus infections. Levels of G-6-PD were determined when patients entered the trial. Most patients were black Americans. G-6-PD-deficient patients were followed serially, with determinations of hemoglobin, haptoglobin, and bilirubin levels, reticulocyte count, and urinalysis. Pretherapy hemoglobin levels were compared with levels during and after therapy. One hundred patients were divided into four groups: group A comprised G-6-PD-deficient patients receiving TMP-SMZ (n = 20); group B, G-6-PD-deficient patients receiving vancomycin (n = 25); and groups C and D, patients with normal G-6-PD levels receiving TMP-SMZ (n = 24) and vancomycin (n = 31), respectively. Groups were comparable in terms of age of patients and duration of therapy. Hemolysis did not occur in any patient receiving TMP-SMZ and occurred in only one patient receiving vancomycin. Both this study and published reports indicate that TMP-SMZ rarely causes hemolysis in a G-6-PD-deficient population.