June 2013
Volume 54, Issue 15
ARVO Annual Meeting Abstract  |   June 2013
Trimethoprim-sulfamethoxazole versus placebo to reduce the risk of recurrences of Toxoplasma gondii retinochoroiditis: randomized controlled clinical trial (ISROT)
Author Affiliations & Notes
  • Joao Felix
    Oftalmologia, Unicamp, Campinas, Brazil
  • Rafael Zacchia
    Oftalmologia, Unicamp, Campinas, Brazil
  • Jaqueline Toribio
    Oftalmologia, Unicamp, Campinas, Brazil
  • Mauricio Nascimento
    Oftalmologia, Unicamp, Campinas, Brazil
  • Carlos Arieta
    Oftalmologia, Unicamp, Campinas, Brazil
  • Heitor Panetta
    Oftalmologia, Unicamp, Campinas, Brazil
  • Valdir Balarin
    Oftalmologia, Unicamp, Campinas, Brazil
  • Rodrigo Lira
    Oftalmologia, Unicamp, Campinas, Brazil
  • Footnotes
    Commercial Relationships Joao Felix, None; Rafael Zacchia, None; Jaqueline Toribio, None; Mauricio Nascimento, None; Carlos Arieta, None; Heitor Panetta, None; Valdir Balarin, None; Rodrigo Lira, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 2936. doi:
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      Joao Felix, Rafael Zacchia, Jaqueline Toribio, Mauricio Nascimento, Carlos Arieta, Heitor Panetta, Valdir Balarin, Rodrigo Lira, ISROT; Trimethoprim-sulfamethoxazole versus placebo to reduce the risk of recurrences of Toxoplasma gondii retinochoroiditis: randomized controlled clinical trial (ISROT). Invest. Ophthalmol. Vis. Sci. 2013;54(15):2936.

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      © ARVO (1962-2015); The Authors (2016-present)

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


This study was a single-center, prospective randomized, double-masked, clinical trial. 81 patients from Campinas, Brazil, with active recurrent Toxoplasma gondii retinochoroiditis were included (a new focus of necrotizing retinochoroiditis with active inflammation either adjacent to or remote from preexisting retinochoroidal scars, with positive IgG for Toxoplasmosis). All patients were successfully treated with 1 tablet of trimethoprim-sulfamethoxazole (800mg/160mg) two times daily for 45 days. After that, two patients drop out of the study. The remaining patients were randomized to group 1 (Trimethoprim-sulfamethoxazole tablet every two days) or group 2 (identical placebo tablet every two days). Block randomization was performed (blocks of 4 patients, 2 in each group) with stratification by gender. The primary outcome was 6-months incidence of recurrent Toxoplasmosis retinochoroiditis, and the secondary outcome was 6-months change of best correct visual acuity/BCVA (ETDRS chart).


A total of 79 patients completed the 6-months follow-up (Figure 1). Demographic data were comparable in the 2 groups (Table 1). The incidence of recurrent Toxoplasmosis retinochoroiditis was 0/40 (0%) at group 1 and 5/39 (12.8%) at group 2 (P = .026). The changes of BCVA were 19 SD 21 letters in group 1 and 20 SD 16 letters (P = .833). No significant adverse events (drug reactions) were registered.


Trimethoprim-sulfamethoxazole compared with placebo may reduce the recurrences of Toxoplasma gondii retinochoroiditis.

Keywords: 734 toxoplasmosis • 422 antibiotics/antifungals/antiparasitics  

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