Comparison of the Safety and Efficacy of Dorzolamide 2% and Brimonidine 0.2% in Patients with Glaucoma or Ocular Hypertension

Purpose: To compare the intraocular pressure (IOP) reduction between dorzolamide 2% and brimonidine 0.2% in primary open-angle glaucoma (POAG) or ocular hypertension (OHT). Methods: This study was a prospective, double-masked, randomized, crossover comparison of dorzolamide 2% (Trusopt®) and brimonidine 0.2% (Alphagan®), three times daily during two six-week study periods. The primary endpoint was mean change from baseline in trough IOP and secondary endpoints were mean change from baseline in IOP one and three hours after dosing. T-tests and a repeated-measures ANOVA were used to statistically evaluate the data. Results: Of 43 patients enrolled, 41 completed the first treatment and 38 completed both treatments. Baseline IOP for dorzolamide was 24.3 mm Hg and brimonidine, 24.6 mm Hg (P = 0.9). Mean IOP reduction at trough was similar for both agents, 3.0 mm Hg (P = 0.96). Reductions at one and three hours were comparable (P = ns). Both agents were well tolerated with adverse events consistent with the package inserts. Dorzolamide was associated with more frequent stinging (P = 0.017) and burning (P < 0.001), while brimonidine was associated with more frequent dry eye (P = 0.04). Conclusions: Dorzolamide and brimonidine, as monotherapy, produced equivalent IOP-lowering efficacy at trough and at one and three hours after instillation, and both were well tolerated.