Azithromycin versus Sulfadiazine and Pyrimethamine for non-vision-threatening toxoplasmic retinochoroiditis: A pilot study

BACKGROUND The purpose of this pilot study is to compare the efficacy and tolerance of azithromycin alone as opposed to standard treatment with sulfadiazine and pyrimethamine for active, non-vision-threatening toxoplasmic retinochoroiditis. MATERIAL/METHODS We conducted a prospective, randomized, institutional clinical study comparing azithromycin to sulfadiazine and pyrimethamine for active, non-vision-threatening toxoplasmic retinochoroiditis. Nineteen out of 75 patients fulfilled inclusion criteria and were randomized into 2 treatment regimens. Nine patients were treated with sulfadiazine and pyrimethamine and 10 patients with azithromycin at a dose of 500 mg qd. Main outcome measures assessed were time to sharpening of lesion borders, time to lesion scarring, time to disease inactivity, and treatment tolerance. RESULTS Azithromycin monotherapy achieved lesion scarring and disease inactivity in all but 1 patient. Although no statistically significant difference was found between the 2 patient groups as regards main outcome measures for treatment efficacy, all median times to endpoints (days) were longer for the azithromycin group - time to sharpening of lesion borders on clinical evaluation (25.5 vs. 24) and masked evaluation of photographs (30.5 vs. 24), time to lesion scarring on clinical evaluation (73 vs. 47) and masked evaluation of photographs (71.5 vs. 36) and time to disease inactivity (73 vs. 49). Treatment tolerance was significantly better for the azithromycin group (p=0.0005). CONCLUSIONS Azithromycin monotherapy at a dose of 500 mg per day was shown to be effective and well-tolerated for the treatment of active, non-vision-threatening toxoplasmic retinochoroiditis. Duration of treatment was clinically longer for the azithromycin group.