Which medication does NOT decrease salivary flow?

Correct answer: C. Pilocarpine

• A. Amitriptyline, a tricyclic antidepressant, has strong anticholinergic activity and is one of the most xerostomia-inducing drugs in common use.
• B. Diphenhydramine is a first-generation antihistamine with significant anticholinergic effect and causes dry mouth.
• C. CORRECT — this one INCREASES saliva. PILOCARPINE is a muscarinic AGONIST (parasympathomimetic) prescribed specifically to STIMULATE salivary flow in Sjögren syndrome and post-radiation xerostomia. It requires residual functioning acinar tissue. Adverse effects: sweating, flushing, GI upset; contraindicated in uncontrolled asthma and narrow-angle glaucoma. Cevimeline is the related M3-selective agent.
• D. Scopolamine is a classic ANTIcholinergic (antimuscarinic) used for motion sickness — it markedly reduces salivation.

Note: Anticholinergic = DRY. Cholinergic agonist = WET. Pilocarpine and cevimeline are the two drugs that go the other way.