For a patient suffering from dry mouth due to reduced salivary secretion after radiation therapy, which drug would be beneficial?

Pilocarpine is a muscarinic agonist, meaning it stimulates the muscarinic receptors in the salivary glands. This stimulation can lead to increased salivary secretion, making it particularly beneficial for patients experiencing dry mouth, or xerostomia, which can occur after radiation therapy targeting the head and neck.

In conditions where the salivary glands are functioning but the secretion is low due to damage or other factors, pilocarpine effectively mimics the action of acetylcholine, enhancing saliva production. It is specifically indicated for conditions like Sjögren's syndrome and radiation-induced xerostomia, where salivary gland function is compromised.

In contrast, other choices either do not help in increasing salivary secretion or have results contrary to what is needed for a patient with dry mouth. Acetylcholine, while it could theoretically increase saliva production, is not commonly used due to its rapid breakdown by acetylcholinesterase and potential for systemic side effects. Echothiophate, an acetylcholinesterase inhibitor, is used primarily in treating glaucoma and would not be appropriate for stimulating saliva production. Atropine is an anticholinergic agent that decreases secretions, so it would exacerbate dry