A prospective, randomized trial of pyrimethamine and azithromycin vs pyrimethamine and sulfadiazine for the treatment of ocular toxoplasmosis.

OBJECTIVE: To compare the effects of two treatment regimens, one of which included azithromycin, for the treatment of sight-threatening (near optic disk or fovea) ocular toxoplasmosis.

DESIGN: Prospective, randomized open-labeled multicenter study, masked in part with regard to evaluation.

METHODS: PARTICIPANTS TOTAL ENROLLMENT: 46 patients with sight-threatening ocular toxoplasmosis; pyrimethamine and azithromycin group: 24 patients; pyrimethamine and sulfadiazine group: 22 patients.

INTERVENTION: Patients were randomized into two treatment regimens. Group 1 was treated with pyrimethamine and azithromycin complemented with folinic acid and the addition of prednisone from day 3. Group 2 was treated with pyrimethamine and sulfadiazine complemented with folinic acid and the addition of prednisone from day 3. Patients used study medications daily for 4 weeks. Ocular and laboratory examinations were performed at least weekly during the observation period. The study was masked in part with regard to evaluation.

MAIN OUTCOME MEASURES: An assessment was made of the time to resolution of the intraocular inflammatory activity, the size of the retinochoroidal lesion, and visual acuity before and after the treatment as well as all adverse effects of treatments.

RESULTS: Adverse effects were more frequent in the pyrimethamine/sulfadiazine group (P <.04), and three patients in this group had to discontinue treatment. The time to resolution of inflammatory activity, decrease in size of retinochoroidal lesions, and optimal visual acuity did not differ between the two treatment groups. The number of patients who developed recurrences during the first year after treatment was similar for both groups.

CONCLUSIONS: The efficacy of the multidrug regimen with pyrimethamine and azithromycin was similar to the standard treatment with pyrimethamine and sulfadiazine. However, the frequency and severity of adverse effects was significantly lower with a regimen containing pyrimethamine and azithromycin. Multidrug therapy with the combination of pyrimethamine and azithromycin appears to be an acceptable alternative for treatment of sight-threatening ocular toxoplasmosis.