For acute angle-closure glaucoma, which medication is used as a first-line systemic therapy?

For acute angle-closure glaucoma, which medication is used as a first-line systemic therapy?

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

Answer: (C)

Lowering intraocular pressure quickly is the priority in acute angle-closure glaucoma. Acetazolamide fits as the first-line systemic option because it acts rapidly to reduce the production of aqueous humor. It’s a carbonic anhydrase inhibitor that works in the ciliary body to decrease bicarbonate formation and, consequently, fluid secretion into the anterior chamber. Give it by mouth or IV, and you typically see a meaningful drop in intraocular pressure within hours, which buys time for definitive treatment like laser or surgical peripheral iridotomy. Mannitol is also used to lower pressure fast, but it’s usually reserved for more severe cases or when acetazolamide cannot be used, since it’s an IV osmotic agent with a different risk profile. Pilocarpine, a topical miotic, is helpful after some pressure reduction has begun, to open the angle, but by itself it isn’t the rapid systemic therapy you start with. Epinephrine can worsen the angle closure by causing pupil dilation, so it isn’t appropriate here. So the best first-line systemic choice is acetazolamide because it quickly decreases aqueous humor production, addressing the urgency of the situation.

Lowering intraocular pressure quickly is the priority in acute angle-closure glaucoma. Acetazolamide fits as the first-line systemic option because it acts rapidly to reduce the production of aqueous humor. It’s a carbonic anhydrase inhibitor that works in the ciliary body to decrease bicarbonate formation and, consequently, fluid secretion into the anterior chamber. Give it by mouth or IV, and you typically see a meaningful drop in intraocular pressure within hours, which buys time for definitive treatment like laser or surgical peripheral iridotomy.

Mannitol is also used to lower pressure fast, but it’s usually reserved for more severe cases or when acetazolamide cannot be used, since it’s an IV osmotic agent with a different risk profile. Pilocarpine, a topical miotic, is helpful after some pressure reduction has begun, to open the angle, but by itself it isn’t the rapid systemic therapy you start with. Epinephrine can worsen the angle closure by causing pupil dilation, so it isn’t appropriate here.

So the best first-line systemic choice is acetazolamide because it quickly decreases aqueous humor production, addressing the urgency of the situation.