Which pairing correctly matches a pharmacologic class used to treat overactive bladder with a common side effect?

• A. Beta-3 agonists — dry mouth.
• B. Antimuscarinics — dry mouth.
• C. Antimuscarinics — weight gain.
• D. Beta-3 agonists — hypotension.

Answer: (B)

Blocking muscarinic receptors in the bladder with antimuscarinic drugs is a common approach to treating overactive bladder because it reduces involuntary detrusor contractions. A classic side effect of this anticholinergic action is dry mouth, since blocking muscarinic receptors decreases saliva production from the salivary glands.

Beta-3 agonists work by stimulating beta-3 receptors on the detrusor to relax the bladder and increase capacity; their common side effects are more like hypertension or tachycardia, not dry mouth. Weight gain isn’t a typical hallmark of antimuscarinics, and hypotension isn’t a typical side effect of beta-3 agonists.

So the pairing that fits the known drug action and side-effect profile is antimuscarinics with dry mouth.