Which drug class reduces salivary flow?

• A. Antidepressants
• B. Antibiotics
• C. Analgesics
• D. Antiinflammatories

Answer: (A)

Medicines that dampen parasympathetic stimulation to the salivary glands can cause dry mouth, and antidepressants often have anticholinergic activity. By blocking acetylcholine on muscarinic receptors in the salivary glands, these drugs reduce saliva production, leading to xerostomia. This class effect is well documented, especially with older tricyclic antidepressants, though some other antidepressants can contribute to dryness to varying degrees. The other drug classes listed do not provide a consistent, broad mechanism for reducing saliva, so they are not the typical cause of decreased salivary flow. In practice, dry mouth from antidepressants increases caries risk and mucosal discomfort, so management focuses on hydration, saliva substitutes or stimulants, fluoride protection, and coordinating with the prescriber if possible.