Which of the following may precipitate acute angle-closure glaucoma?

• A. Metoclopramide
• B. Timolol
• C. Glyburide
• D. Acetazolamide

Answer: (A)

Acute angle-closure glaucoma is triggered when something causes the pupil to dilate and the iris to crowd the drainage angle, abruptly blocking outflow and rapidly increasing intraocular pressure. Drugs that can cause pupillary dilation or have anticholinergic-like effects make this more likely in people with narrow angles. Metoclopramide can produce pupillary dilation in some patients, so in a predisposed eye it can precipitate an acute attack. In contrast, the other drugs listed don’t promote pupil dilation in a way that would trigger this emergency: timolol and acetazolamide are used to lower intraocular pressure, and glyburide has no known effect on the pupil or angle. If symptoms like severe eye pain, halos, or headache occur, urgent ophthalmologic evaluation is essential.