Brimonidine Tartrate 0.15%, Dorzolamide Hydrochloride 2%, and Brinzolamide 1% Compared as Adjunctive Therapy to Prostaglandin Analogs

Objective: To compare the efficacy of brimonidine, dorzolamide, and brinzolamide in reducing intraocular pressure (IOP) when used as adjunctive therapy to a prostaglandin analog (PGA). Design: Randomized, controlled, investigator-m asked, single-site, parallel-group clinical trial. Participants: One hundred twenty eyes of 120 patients with open-angle glaucoma or ocular hypertension who had inadequate IOP control after at least 6 weeks of monotherapy with a once-daily PGA (bimatoprost, latanoprost, or travoprost). Intervention: Study eyes were assigned randomly to adjunctive treatment with thrice-daily brimonidine tartrate 0.15% (n = 41), dorzolamide hydrochloride 2% (n = 40), or brinzolamide 1% (n = 39) for 4 months. Main Outcome Measures: Efficacy was evaluated by IOP measured at 10 AM and 4 PM at baseline, month 1, and month 4. Results: The mean IOP at each hour at PGA-treated baseline was comparable among treatment groups. After initiation of adjunctive therapy, the mean IOP was lower and the mean change from baseline IOP was greater in the brimonidine group than in either the dorzolamide group or the brinzolamide group at 10 AM and 4 PM at months 1 and 4 (P<0.001). After 4 months of adjunctive treatment, the mean IOP reduction from baseline at 10 AM and 4 PM was 4.8 mmHg (21%) and 3.8 mmHg (19%) with brimonidine, 3.4 mmHg (16%) and 2.8 mmHg (14%) with dorzolamide, and 3.4 mmHg (16%) and 2.6 mmHg (13%) with brinzolamide (P<0.001 for brimonidine vs. dorzolamide and brinzolamide at each time point). Each of the study drugs was well tolerated, and all patients completed the study. Conclusions: The addition of brimonidine to a PGA provided greater IOP lowering than the addition of either dorzolamide or brinzolamide. Further studies are needed to evaluate the relative long-term efficacy and tolerability of these medications as adjunctive therapy to a PGA.