Chapter review

Fitzgerald PMHNP board review. ch17. Prescribing in the Older Adult: Doing More by Doing Less. This is drive 4 of 4. When I say Pause. Answer. wait, then I will give the answer. New section. Prescribing cascades, interactions, and dangerous-to-miss safety alerts. Topic. Practice Question: Drug-Induced Dementia Presentation. Bottom Line Summary. * **Medication reconciliation is the mandatory initial assessment** for any older adult presenting with new or rapidly accelerating cognitive decline. * **First-generation antihistamines, tricyclic antidepressants, and oral bladder antimuscarinics** possess potent central anticholinergic activity that induces reversible cognitive impairment and delirium in older adults. * **Prescribing cascades occur when an adverse drug reaction is misdiagnosed** as a new medical condition, leading to additional inappropriate prescriptions. * **Co-prescribing donepezil with oxybutynin represents a major prescribing cascade** because the muscarinic blocker directly neutralizes the central acetylcholinesterase inhibitor. * **The American Geriatrics Society Beers Criteria strongly advises avoiding high-anticholinergic drugs** in older adults due to elevated risks of cognitive decline, urinary retention, constipation, and falls. * **Age-related declines in renal clearance cause drug accumulation** even when serum creatinine remains within normal reference ranges due to decreased muscle mass. * **Deprescribing potentially inappropriate medications must precede** escalating dementia pharmacotherapy or adding second-line cognitive enhancers. Main Testable Concepts. Drug-Induced Cognitive Impairment in Older Adults. * **Core Pathology**: Central M1 muscarinic receptor blockade impairs cholinergic neurotransmission in the hippocampus and cortex, producing symptoms that mimic or worsen major neurocognitive disorder. * **Key Offending Medications**: **Diphenhydramine**, **hydroxyzine**, **amitriptyline**, **doxepin**, **oxybutynin**, **tolterodine**, **cyclobenzaprine**, and **alprazolam**. * **First-line**: Conduct a comprehensive medication review and calculate cumulative anticholinergic burden using validated tools or Beers Criteria guidance. * **Safety alert**: High anticholinergic burden in older adults significantly increases 1-year mortality, fall risk, acute delirium, and emergency room visits. * **Board trap**: Assuming recent memory loss in an 80-year-old patient represents irreversible Alzheimer disease without first auditing recent medication changes or OTC sleep aid use. Prescribing Cascades and Cholinesterase Neutralization. * **Mechanism**: A patient prescribed **donepezil** develops urge incontinence as a cholinergic side effect; the clinician prescribes **oxybutynin** to treat incontinence, which crosses the blood-brain barrier and blocks the cholinergic boost provided by **donepezil**. * **Clinical Result**: Cognitive scores drop, prompting the clinician to increase the **donepezil** dose or add **memantine**, escalating the cascade. * **First-line**: Deprescribe the non-essential anticholinergic agent or switch to a uro-selective beta-3 agonist like **mirabegron** that lacks central anticholinergic activity. Compare and Distinguish. Drug-Induced Cognitive Impairment vs Primary Neurocognitive Disorder. Drug-Induced Cognitive Impairment * **Think**: Subacute onset of confusion and memory loss temporally linked to new prescription additions, dose increases, or over-the-counter anticholinergic sleep aids. * **Priority**: Discontinue offending drugs and reassess cognitive baseline over 4 to 8 weeks. * **Boards are testing**: Recognition of reversible drug toxicity and application of deprescribing principles. Primary Neurocognitive Disorder * **Think**: Insidious, slowly progressive cognitive decline occurring over months to years without acute temporal relation to new drug starts. * **Priority**: Establish baseline cognitive testing, rule out metabolic and infectious causes, and initiate evidence-based cholinesterase inhibitors if appropriate. * **Boards are testing**: Standard diagnostic criteria and longitudinal management of primary dementias. Practice Question: Drug-Induced Dementia Presentation. Question 1. An 78-year-old woman with mild neurocognitive disorder is brought to the clinic by her daughter due to a rapid 3-month decline in memory, increased confusion, and new daytime drowsiness. Her medication list includes **donepezil** 10 mg daily, **oxybutynin** 10 mg daily added 3 months ago for urge incontinence, **diphenhydramine** 25 mg at bedtime for insomnia, and **hydrochlorothiazide** 25 mg daily. Physical examination, vital signs, and urinalysis are unremarkable. What is the most appropriate initial action by the PMHNP? A) Increase **donepezil** to 23 mg daily to treat accelerating dementia. B) Discontinue **diphenhydramine** and taper **oxybutynin** while re-evaluating cognitive function. C) Order a brain MRI to evaluate for acute cerebrovascular events. D) Initiate **memantine** 5 mg daily as combination therapy. **Pause.** **Answer**: B **Why It Is Correct**: Discontinuing **diphenhydramine** and tapering **oxybutynin** is the essential initial step because both drugs exert strong central anticholinergic effects that induce cognitive impairment in older adults. **Diphenhydramine** is a first-generation H1 antagonist explicitly highlighted on the Beers Criteria as inappropriate for older adults due to severe anticholinergic toxicity, delirium, and fall risks. **Oxybutynin** is a central muscarinic antagonist that directly antagonizes the therapeutic cholinergic effect of **donepezil**, creating a classic prescribing cascade. Eliminating this anticholinergic burden allows the clinician to measure the patient's true cognitive baseline. **Why the Other Choices Are Wrong**: * **A:** Increasing **donepezil** escalates drug exposure without resolving the ongoing pharmacologic antagonism caused by **oxybutynin** and **diphenhydramine**. * **C:** Ordering a brain MRI is premature before addressing clear, reversible medication-induced causes of cognitive decline. * **D:** Adding **memantine** escalates the prescribing cascade by adding another psychotropic drug without removing the underlying offending agents. **Test-Taking Pearl**: When an older adult presents with sudden or subacute cognitive decline, always audit the medication list for anticholinergic and sedative drugs before adding new psychiatric medications or ordering complex imaging. Next Study Step. Review the **2019 American Geriatrics Society Beers Criteria and START/STOPP Screening Tools** to master specific drug classes, contraindications, and high-risk prescribing cascades in geriatric psychopharmacology. Next. End of this drive.