Clinical experience with brimonidine 0.2% and timolol 0.5% in glaucoma and ocular hypertension

Abstract

The ocular hypotensive efficacy and safety of brimonidine tartrate 0.2%, a highly selective alpha 2-adrenergic agonist, was compared with that of timolol 0.5%, a nonselective beta-blocker in two multicenter, randomized, double-masked studies. Combined data from a 12-month completed study and 6-month interim data from an ongoing study are reported. Efficacy and safety were evaluated at baseline, weeks 1 and 2, and months 1, 2, 3, 6, 9, and 12. Intraocular pressure (IOP) was measured at peak (2 hours after the morning dose) and trough (12 hours after the evening dose). Patients (n = 926) instilled either brimonidine tartrate 0.2% or timolol maleate 0.5% twice daily. At peak, the mean decreases from baseline IOP ranged from 5.9 ± 3.2 mm Hg to 7.6 ± 3.6 mm Hg for brimonidine and 6.0 ± 3.4 mm Hg to 6.6 ± 3.6 mm Hg for timolol (p < 0.001 within groups compared with baseline). No significant between-group differences were seen at peak except for weeks 1 and 2 and month 3 (p ≤ 0.04), when brimonidine had lower mean IOP. At trough the mean decreases from baseline ranged from 3.7 ± 4.0 mm Hg to 5.0 ± 3.0 mm Hg for brimonidine and 5.9 ± 3.4 to 6.6 ± 3.0 for timolol. A significant between-group difference was seen at trough at all visits (< 0.001), when timolol had a lower mean IOP. Brimonidine and timolol showed sustained efficacy. Both drugs were well-tolerated. The brimonidine group had more ocular allergy, oral dryness and conjunctival follicles. The timolol group had more burning and stinging. In the brimonidine group, 38/513 (7.4%) discontinued treatment due to ocular allergy. The timolol group had significantly lower mean heart rate compared to baseline. The effect on blood pressure was minimal for both drugs. Briinonidine showed efficacy similar to timolol and a relatively low rate of ocular allergy. Brimonidine 0.2% administered twice daily is an effective and safe ocular hypotensive agent that maintains IOP-lowering in chronic use.