Purpose: To compare the IOP-lowering efficacy of brimonidine and dorzolamide as adjunctive therapy to beta-blockers in patients with glaucoma or ocular hypertension.
Design: A prospective, investigator–masked, multicenter, parallel design clinical trial.
Participants: One hundred six patients with IOP inadequately controlled on topical beta-blocker monotherapy.
Methods: Patients were randomized to either brimonidine 0.2% BID or dorzolamide 2% TID as adjunctive therapy for 3 months. Efficacy was determined by reduction in IOP from baseline. After 1 month of adjuctive therapy, patients who failed to meet a target 15% IOP reduction at peak drug effect were crossed over to the other study medication.
Results: After 1 month of adjunctive therapy, the mean daily IOP reduction was significantly greater with brimonidine (4.40 mm Hg, 20.42%) than with dorzolamide (3.0 mm Hg, 14.36%; P=.033). At peak drug effect, the mean IOP reduction in brimonidine-treated patients was 5.95 mm Hg (27.6%) and 4.11 mm Hg (19.65%) in dorzolamide-treated patients (P=.007). Significantly more patients treated with brimonidine (44/51, 86.3%) than with dorzolamide (29/47, 61.7%) achieved the target 15% IOP reduction at month 1 (P=.005). At month 3, the mean daily IOP reduction was 4.98 mm Hg in the brimonidine group and 3.15 mm Hg in the dorzolamide group (P=.092). At peak drug effect, the mean IOP reduction with brimonidne was 6.93 mm Hg, versus 4.06 mm Hg with dorzolamide (P=.060).
Conclusion: Brimonidine BID produced greater mean decreases
in IOP and was effective in more patients than dorzolamide TID when used as
adjunct therapy to beta-blockers.