Background: Digestive features and metabolic acidosis have been observed in patients with Pneumocystis carinii pneumonia treated with intravenous high dose co-trimoxazole.
Methods: To evaluate this phenomenon, a retrospective study of 22 patients (group A) and a prospective study of 12 patients (group B) were carried out. Group B patients were investigated following a protocol lasting for the 21 days of treatment.
Results: Metabolic acidosis developed in 23 (67%) of the overall number of study patients, and it was associated with digestive features such as nausea, vomiting and epigastralgia in 12. One patient had digestive features without metabolic acidosis. Metabolic acidosis developed early, between the days 4 and 7 of administration of the drug. The mean value of bicarbonate at the onset of therapy was 24,55 mEq; the mean value in the patients with metabolic acidosis was 16,43 mEq. The overall mean value of base excess at the onset of therapy was -2,39, and it was -8,46 in the patients who developed metabolic acidosis.
Conclusions: As in all patients other causes of metabolic acidosis were ruled out, it became obvious that intravenous co-trimoxazole was directly related to the development of digestive features and metabolic acidosis, which disappeared with bicarbonate administration or with cessation of therapy.