A short term study of the additive effect of timolol and brimonidine on intraocular pressure

Abstract

Purpose. To evaluate the additive ocular hypotensive effect of the combination of brimonidine and timolol on intraocular pressure (IOP) reduction in patients with glaucoma. Methods. This was a prospective, randomized, double-masked, crossover study in 20 patients with primary open angle glaucoma (POAG) on therapy receiving timolol maleate 0.5% twice daily, with IOP greater than or equal to 22 mmHg in one eye. The treatment period was 3 weeks and during this period timolol + brimonidine or timolol + placebo were applied topically twice daily and IOP, blood pressure, heart rate and pupil size were measured. Results. Combined therapy (timolol + brimonidine) had clinically significant IOP-lowering effect during the treatment period (P < 0.01). The mean diurnal IOP was significantly reduced by an average of 5.1-5.9 mmHg (21.2-24.5%) compared with baseline value. The timolol + placebo combination had no clinically significant IOP-lowering effect (P > 0.05). No clinically significant side effects were observed during the treatment of both groups. Conclusions. This study showed that the combination of topically applied brimonidine and timolol cause a marked and sustained IOP reduction.