Brimonidine

Abstract

Brimonidine tartrate is a highly selective ₂-adrenergic receptor agonist indicated for the chronic treatment of glaucoma and ocular hypertension. Glaucoma, a serious worldwide public health problem causing blindness in 5.2 million people, is treated by drugs that lower the intraocular pressure (IOP), a primary risk factor in glaucomatous optic neuropathy. Currently, beta-blockers are the most common therapy. In two 12-month clinical comparison trials with timolol 0.5% (n = 926), twice-daily brimonidine produced IOP lowering comparable to twice-daily timolol. In a 3-month trial with betaxolol 0.25% suspension (n = 206), twice-daily brimonidine was more effective in lowering IOP than twice-daily betaxolol. Brimonidine was well-tolerated ocularly and systemically in these trials. It caused no clinically significant mean changes in heart rate or blood pressure. Brimonidine produced no significant effect on FEV1 in clinical trials, and it is not contraindicated in patients with cardiopulmonary disease. Brimonidine 0.2% dosed twice daily has clinical utility as a first-line drug therapy. It is an effective and safe alternative to beta-blockers, particularly in patients at risk for pulmonary or cardiovascular disease. It decreases aqueous humour production and increases uveoscleral outflow, and has an additive ocular hypotensive effect used concomitantly with other agents. Brimonidine has demonstrated neuroprotective properties in laboratory animal studies. Additional studies are warranted to determine whether brimonidine has clinical benefit in protecting the optic nerve head from glaucomatous damage. Brimonidine is an important contribution to glaucoma management.