Trimethoprim-sulfamethoxazole and hypouricemia

Background. Hypouricemia has been reported in a substantial fraction of patients with AIDS and attributed to an HIV-related renal mate transport defect. We tested the alternative hypothesis that hypouricemia was associated with the administration of high-dose trimethoprim-sulfamethoxazole (TMP-SMX). Methods. Sociodemographic, clinical, and repeated laboratory data on 45 hospitalized patients with Pneumocystis carinii pneumonia (PCP) with and without HIV infection, were abstracted by a blinded reviewer. The primary outcome of interest was the percent change in serum uric acid concentration from baseline to hospital day 5 +/- 1. Results. Subjects who received TMP-SMX were older (mean age 44.8 vs. 37.0, p = 0.02), less likely to be HIV-seropositive (61% vs. 94%, p = 0.01), and more Likely to have received glucocorticoid therapy (75% vs. 35%, p = 0.01) than those who re received pentamidine, dapsone-trimethoprim, clindamycin-primaquine, sulfadiazine-pyramethamine, or a combination of these agents. The administration of TMP-SMX was associated with a 37% +/- 12% reduction in serum uric acid concentration, adjusting for the effects of age, sex, race, HIV antibody status, renal function, serum sodium, and the use of diuretics and glucocorticoids (p = 0.005). Conclusion. Among a diverse cohort of hospitalized patients with PCP, treatment with high-dose TMP-SMX was strongly associated with a reduction in serum uric acid concentration over time.