Pharmacology · patient case with 5 questions
The Geriatric Patient
demo: 90-year-old female
chief: “My mouth is always dry and this tooth is throbbing.”
history: Osteoporosis, mild renal impairment, hypertension. Ambulates with a walker.
meds: Alendronate, methotrexate, zoledronate infusions in the past, hydrochlorothiazide
findings: Generalized xerostomia. Tooth #30 with a periapical abscess requiring antibiotic coverage. Panoramic radiograph shows thinned mandibular cortices.
Question 1
When prescribing an antibiotic for this 90-year-old patient, which physiologic change is most important to consider?
Show answer and explanation
Correct answer: C. Decreased glomerular filtration rate from age-related renal decline
- A. Hepatic metabolism decreases with age rather than increases, and hepatic blood flow declines.
- B. Gastric acid production typically decreases with age, which can alter absorption of pH-dependent drugs.
- C. Correct. GFR falls progressively with age, so renally cleared drugs accumulate. Dose reduction or interval extension is often required in the very elderly.
- D. Serum albumin tends to fall in the elderly, increasing the free fraction of highly protein-bound drugs.
Question 2
This patient takes methotrexate and a bisphosphonate for osteoporosis. Which radiographic finding is most expected?
Show answer and explanation
Correct answer: A. Thinning of the mandibular cortical bone
- A. Correct. Osteoporosis reduces bone mineral density, and the mandibular inferior cortex is a recognized site where thinning and porosity can be appreciated on a panoramic radiograph.
- B. That pattern suggests dentin dysplasia or pulpal calcification, not osteoporosis.
- C. Periapical radiolucencies indicate pulpal necrosis, unrelated to metabolic bone disease.
- D. Generalized PDL widening suggests occlusal trauma or scleroderma, not osteoporosis.
Question 3
Which of the following medications is LEAST likely to cause this patient's xerostomia?
Show answer and explanation
Correct answer: A. Zoledronate
- A. Correct. Zoledronate is a bisphosphonate. Its salient oral risk is medication-related osteonecrosis of the jaw, not salivary hypofunction.
- B. Oxybutynin is an antimuscarinic used for overactive bladder and predictably causes dry mouth.
- C. Diphenhydramine is a first-generation antihistamine with strong anticholinergic activity — a classic cause of dry mouth.
- D. Tricyclic antidepressants are among the most reliably xerostomic drug classes.
Question 4
Each of the following is genuinely associated with xerostomia EXCEPT:
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Correct answer: B. Advancing age by itself
- A. Radiation to the salivary glands causes serous acinar loss and often permanent hyposalivation.
- B. Correct — this is the exception. Age alone does not cause clinically significant salivary hypofunction. The apparent association is driven by the medications and comorbidities that accumulate with age.
- C. Sjögren syndrome is an autoimmune exocrinopathy that directly destroys salivary and lacrimal parenchyma.
- D. Anticholinergics block muscarinic receptors on salivary acini, reducing secretion.
Question 5
If this patient also had documented xerostomia, which medication would you specifically avoid?
Show answer and explanation
Correct answer: A. Atropine
- A. Correct. Atropine is an antimuscarinic and would deepen the dry mouth substantially.
- B. Cevimeline is likewise a muscarinic agonist indicated for Sjögren-related dry mouth.
- C. Pilocarpine is a muscarinic agonist used to treat xerostomia, not worsen it.
- D. Saliva substitutes are purely palliative and carry no risk of worsening the condition.