Brimonidine is an alpha-2 adrenergic agonist with which primary effect on aqueous dynamics?

Brimonidine is an alpha-2 adrenergic agonist with which primary effect on aqueous dynamics?

• A. Increases aqueous production
• B. Decreases aqueous production
• C. Decreases aqueous production and increases uveoscleral outflow
• D. Increases uveoscleral outflow

Answer: (C)

Brimonidine lowers intraocular pressure by a dual action on aqueous humor dynamics. It binds to alpha-2 receptors in the ciliary body, which reduces adenylate cyclase activity and lowers cAMP, leading to decreased aqueous humor production. At the same time, it relaxes the ciliary muscle, increasing uveoscleral outflow. So the best choice reflects both reduced production and enhanced outflow through the uveoscleral pathway. The other options miss this dual effect by describing production only or outflow only.

Brimonidine lowers intraocular pressure by a dual action on aqueous humor dynamics. It binds to alpha-2 receptors in the ciliary body, which reduces adenylate cyclase activity and lowers cAMP, leading to decreased aqueous humor production. At the same time, it relaxes the ciliary muscle, increasing uveoscleral outflow. So the best choice reflects both reduced production and enhanced outflow through the uveoscleral pathway. The other options miss this dual effect by describing production only or outflow only.