TRIMETHOPRIM SULFAMETHOXAZOLE AND METABOLIC-ACIDOSIS IN HIV-INFECTED PATIENTS/

OBJECTIVE: TO describe a retrospective study of six HIV-positive indiv iduals with compensated metabolic acidosis while receiving intravenous trimethoprim/sulfamethoxazole (TMP/SMX). CASE SUMMARY: Six HIV-infect ed patients were treated for Pneumocystis carinii pneumonia (PCP) with high-dose intravenous TMP/SMX. In spite of a favorable clinical and r adiologic course, all six patients developed compensated metabolic aci dosis 3-5 days after the start of treatment. This potential complicati on of TMP/SMX use was successfully managed with conservative treatment (cessation of therapy with or without additional administration of in travenous bicarbonate). DISCUSSION: TMP/SMX is first-line therapy for PCP in HIV-positive individuals, despite a high frequency of toxic eff ects in these patients. In addition to the cases reported here, only t wo other reports of metabolic acidosis secondary to TMP/SMX use in HIV -infected patients have been published in the literature. The precise mechanism of this untoward effect is not fully understood, although re nal tubular acidosis induced by TMP/SMX could be implicated. CONCLUSIO NS: TMP/SMX toxicity should be considered in the differential diagnosi s of HIV-infected patients with acute metabolic acidosis. Metabolic ac idosis can be expected to resolve shortly after discontinuation of the drug.