What are the contraindications for using anticholinergic drugs in patients with glaucoma?

Anticholinergic drugs are contraindicated in patients with glaucoma primarily because they can increase intraocular pressure and exacerbate the condition. These medications work by blocking the action of acetylcholine on muscarinic receptors, which can lead to pupil dilation (mydriasis). When the pupil dilates, it can impair aqueous humor outflow from the eye, potentially increasing intraocular pressure. For individuals with glaucoma, especially angle-closure glaucoma, this rise in pressure can lead to more severe symptoms and complications.

In contrast, while urinary retention, a decrease in heart rate, and slowed digestion are side effects associated with anticholinergic agents, they are not directly related to the mechanism by which these medications aggravate glaucoma. Therefore, the risk they pose specifically to ocular health makes the second option the most relevant and concerning contraindication.