Which medication increases aqueous humor outflow in acute angle-closure glaucoma?

Which medication increases aqueous humor outflow in acute angle-closure glaucoma?

• A. Timolol
• B. Acetazolamide
• C. Pilocarpine
• D. Mannitol

Answer: (C)

In acute angle-closure glaucoma, opening the blocked drainage pathway to boost outflow is the key action. Pilocarpine is a direct muscarinic receptor agonist that causes the ciliary muscle to contract and the pupil to constrict. This mechanical effect pulls the iris away from the trabecular meshwork, widens the iridocorneal angle, and increases aqueous humor outflow through the conventional pathway. Other options mainly reduce the production of aqueous humor rather than increasing its outflow: timolol and acetazolamide lower formation, and mannitol lowers intraocular pressure by osmotic means without specifically increasing outflow. In practice, you may lower IOP first with agents like acetazolamide or mannitol, then administer pilocarpine to promote reopening of the angle and enhanced outflow.

In acute angle-closure glaucoma, opening the blocked drainage pathway to boost outflow is the key action. Pilocarpine is a direct muscarinic receptor agonist that causes the ciliary muscle to contract and the pupil to constrict. This mechanical effect pulls the iris away from the trabecular meshwork, widens the iridocorneal angle, and increases aqueous humor outflow through the conventional pathway.

Other options mainly reduce the production of aqueous humor rather than increasing its outflow: timolol and acetazolamide lower formation, and mannitol lowers intraocular pressure by osmotic means without specifically increasing outflow. In practice, you may lower IOP first with agents like acetazolamide or mannitol, then administer pilocarpine to promote reopening of the angle and enhanced outflow.