Trimethoprim-sulfamethoxazole versus placebo to reduce the risk of recurrences of Toxoplasma gondii retinochoroiditis: randomized controlled clinical trial.

PURPOSE: To compare the effects of trimethoprim-sulfamethoxazole vs placebo in reducing the risk of recurrences of Toxoplasma gondii retinochoroiditis.

DESIGN: Single-center, prospective randomized double-masked clinical trial.

METHODS: A total of 95 patients from Campinas, Brazil, with active recurrent Toxoplasma gondii retinochoroiditis were included. The initially active toxoplasmosis lesions were successfully treated in all cases using trimethoprim-sulfamethoxazole (800 mg/160 mg) twice daily for 45 days. Subsequently, 5 patients dropped out of the study. The remaining patients were randomized to Group 1 (trimethoprim/sulfamethoxazole tablet every 2 days) or Group 2 (identical placebo tablet every 2 days). Randomization was 1:1, was stratified by sex, and used block sizes of 4. The primary outcome was recurrent toxoplasmosis retinochoroiditis within 1 year, and the secondary outcome was a 1-year change in best-corrected visual acuity (BCVA) (ETDRS chart).

RESULTS: The incidence of recurrent toxoplasmosis retinochoroiditis within 12 months was 0 of 46 (0%) and 6 of 47 (12.80%) in the trimethoprim-sulfamethoxazole and placebo groups, respectively (P = .026). Visual acuity improvements in the 2 groups were similar. No treatment-limiting toxicity was observed.

CONCLUSIONS: Trimethoprim/sulfamethoxazole therapy resulted in a 100% reduction in the recurrence of Toxoplasma gondii retinochoroiditis over 1 year of treatment.