Which medication should be avoided in a patient with sialolithiasis?

• A. Benadryl
• B. Ipratropium
• C. Loop diuretic
• D. ASA

Answer: (B)

In sialolithiasis, anything that markedly decreases salivary flow can worsen duct obstruction and symptoms because saliva helps flush the ducts and prevent stone formation. Medications with anticholinergic (muscarinic antagonist) effects reduce saliva production. Ipratropium is an inhaled antimuscarinic bronchodilator, and it blocks muscarinic receptors in the salivary glands, leading to dry mouth and decreased secretion. This makes drainage through the salivary ducts less efficient and can aggravate stone-related symptoms, so it’s the medication you’d want to avoid in this condition. Loop diuretics and ASA don’t notably reduce saliva production, so they aren’t of concern for sialolithiasis in this context. Benadryl has anticholinergic effects too, but the strongest link here is the muscarinic blockade from ipratropium.