Pharmacology · patient case question
What is a DIRECT side effect of Patient A's medication?
Patient case: Adverse drug reactions in two patients
Patient: Two patients presenting the same day
Chief complaint: Patient A: “My front tooth chipped.” Patient B: “I have a really bad infection.”
History: Patient A: 52-year-old male with chronic migraines, taking amitriptyline. Patient B: 19-year-old male, asthma, smoker, documented penicillin allergy, taking albuterol.
Findings: Patient A: Ellis class I fracture of tooth #9. Patient B: acute apical abscess on tooth #3.
Show answer and explanation
Correct answer: A. Xerostomia
- A. CORRECT. Amitriptyline is a TRICYCLIC ANTIDEPRESSANT with strong ANTIMUSCARINIC activity. Blocking muscarinic receptors on salivary acinar cells directly reduces salivary secretion, and xerostomia is among its most common adverse effects. The dental consequences follow predictably — rampant cervical and root caries, candidiasis, and difficulty wearing a prosthesis.
- B. Burning mouth syndrome is a chronic idiopathic pain condition. Interestingly, low-dose tricyclics are used to TREAT it rather than cause it.
- C. Gingival hyperplasia is caused by phenytoin, cyclosporine and dihydropyridine calcium channel blockers, through fibroblast proliferation. Tricyclics do not cause it.
- D. Candidiasis can occur SECONDARY to the xerostomia, since reduced salivary flow removes antimicrobial proteins and mechanical clearance — but it is a downstream consequence, not the direct pharmacological effect the question asks for.
Note: The other reason amitriptyline matters in the operatory: its antimuscarinic and alpha-blocking effects mean epinephrine-containing local anaesthetic can produce an exaggerated pressor response. Limit the dose and aspirate. Orthostatic hypotension on standing from the chair is also common.