Why should Atropine be avoided in glaucoma patients?

Atropine is an anticholinergic agent that can lead to an increase in intraocular pressure, making it particularly concerning for patients with glaucoma. In glaucoma, especially in angle-closure glaucoma, the drainage angle of the eye is already compromised, and any factor that increases intraocular pressure can exacerbate the condition and lead to increased risk of optic nerve damage.

Atropine works by blocking acetylcholine at muscarinic receptors, which causes pupil dilation (mydriasis) and paralysis of the ciliary muscle (cycloplegia). When the pupil dilates, the angle between the iris and cornea can narrow, further hindering proper aqueous humor drainage from the eye, subsequently raising intraocular pressure.

Understanding the mechanisms of how atropine impacts intraocular pressure helps to underscore the importance of avoiding its use in patients with glaucoma, to prevent potential complications related to increased pressure and the risk of acute glaucoma attacks.