Which medications would most likely be responsible for dry mouth in a patient taking multiple drugs?

• A. Carbidopa/Levodopa (Sinemet) and Escitalopram (Lexapro)
• B. Metformin and Lisinopril
• C. Atorvastatin
• D. Amoxicillin

Answer: (A)

Dry mouth from medications occurs when drugs lower saliva production, a condition known as xerostomia. Escitalopram commonly causes dry mouth as a frequent side effect because antidepressants can alter the autonomic control of the salivary glands. When paired with another drug that can affect autonomic function, such as carbidopa/levodopa used for Parkinson’s, the overall risk of reduced salivary flow increases. That combination is therefore most likely to produce dry mouth in a patient taking multiple drugs.

The other pairs aren’t as strongly linked to xerostomia. Metformin with lisinopril isn’t known for causing dry mouth as a prominent side effect, while atorvastatin and amoxicillin are not typical culprits for persistent dry mouth in standard use. In practice, recognizing medication-induced xerostomia helps you address higher caries risk with hydration, fluoride, and saliva substitutes, and by reviewing the patient’s drug list.