Brimonidine

Brimonidine is an alpha-adrenergic agonist and 2-imidazoline derivative that was first introduced in 1996. It is considered to be a third generation alpha-2 aadrenergic receptor agonist, since it displays preferential binding at alpha-2 adrenoceptors over alpha-1 receptors. Brimonidine displays a higher selectivity toward the alpha-2 adrenergic receptors than clonidine or apraclonidine, which are also alpha-2 adrenergic agonists. Alpha-2 adrenergic agonists are members of the ocular hypotensive agent drug class that are used in the chronic treatment of glaucoma. Early treatment and management of glaucoma, which predominantly involves the lowering of intraocular pressure, is critical since glaucoma is considered to be a common cause of blindness worldwide. Ophthalmically, brimonidine is used to lower intraocular pressure by reducing aqueous humor production and increasing uveoscleral outflow. Because it is oxidately stable, brimonidine is associated with fewer reports of ocular allergic reactions compared to other alpha-2 adrenergic agonists. The ophthalmic solution of brimonidine was first approved by the FDA in 1996 as Alphagan and brimonidine is the only selective alpha-adrenergic receptor agonist approved for chronic treatment in glaucoma. Brimonidine is also found in ophthalmic solutions in combination with brinzolamide under the market name Simbrinza for the reduction in intraocular pressure. Unlike nonselective beta-blockers used in ocular hypertension, brimonidine is not associated with significantly adverse cardiopulmonary side effects. Thus brimonidine is an effective and safe alternative to beta-blockers, in patients with, or at high risk for, cardiopulmonary disease. The topical form of brimonidine was approved by the FDA in August 2013 for the symptomatic treatment of persistent facial erythema of rosacea in adults. It is marketed under the brand name Mirvaso. Brimonidine is the first topical treatment approved for facial erythema of rosacea.