PURPOSE: Some patients taking methotrexate (MTX) or mycophenolate mofetil (MMF) experience intolerable side effects at full doses. We evaluated whether dose reduction affected treatment outcomes in uveitis patients. METHODS: Subanalysis of the First-line Antimetabolites as Steroid-sparing Treatment (FAST) uveitis trial. Patients were randomized to receive MTX (25 mg weekly) or MMF (3 g daily). A pre-specified dose reduction protocol could be employed for intolerable side effects. Primary analysis was performed at 6 months. RESULTS: 43/194 patients (22%) required dose reduction. 88/151 patients (58%) on maximum doses and 32/43 patients (74%) on reduced doses were deemed treatment successes at 6 months. The odds ratio point estimate (1.60, 95% CI 0.72-3.74) favored dose-reduction but this was not significant. Following reduction, adverse events improved at the subsequent study visit (79 events reduced to 63 events). CONCLUSION: Dose reduction of antimetabolites was not associated with worse outcomes in this subanalysis of a uveitis trial.