Fall-Risk Medications: Pharmacological Management

Clinical meaning

Fall-risk-increasing drugs (FRIDs) are medication classes whose pharmacological actions directly or indirectly increase the risk of falls, primarily through mechanisms of sedation, orthostatic hypotension, impaired balance, cognitive blunting, and electrolyte disturbance. The NP must understand the specific mechanisms by which each drug class increases fall risk to make informed prescribing decisions. CENTRAL NERVOUS SYSTEM DEPRESSANTS: benzodiazepines (lorazepam, diazepam, clonazepam) enhance GABAergic inhibition causing sedation, impaired psychomotor function, delayed reaction time, and anterograde amnesia; the effect is prolonged in elderly patients due to increased volume of distribution (lipophilic drugs) and decreased hepatic metabolism; Z-drugs (zolpidem, zopiclone) have similar mechanisms and similar fall risk despite marketing as 'safer' alternatives. OPIOIDS (morphine, oxycodone, hydromorphone) activate mu-opioid receptors causing CNS depression, sedation, dizziness, and orthostatic hypotension (through histamine release and vasodilation). CARDIOVASCULAR MEDICATIONS: antihypertensives cause orthostatic hypotension through different mechanisms -- alpha-1 blockers (prazosin, doxazosin) directly block peripheral vasoconstriction, centrally acting agents (clonidine) reduce sympathetic outflow, diuretics (furosemide, hydrochlorothiazide) cause volume depletion and electrolyte abnormalities (hyponatremia, hypokalemia), beta-blockers blunt the compensatory heart rate response to postural change, and ACE inhibitors/ARBs reduce angiotensin II-mediated vasoconstriction. ANTICHOLINERGIC MEDICATIONS (diphenhydramine, oxybutynin, amitriptyline) cause confusion, blurred vision, urinary retention (leading to urgency after catheter removal), dry mouth, and constipation -- the anticholinergic burden is cumulative across multiple medications. ANTIPSYCHOTICS (haloperidol, quetiapine, risperidone) cause sedation, extrapyramidal symptoms (rigidity, bradykinesia affecting gait), orthostatic hypotension (alpha-1 blockade), and anticholinergic effects. ANTIDEPRESSANTS: SSRIs (sertraline, citalopram) cause hyponatremia through SIADH (particularly in elderly) and impair balance; TCAs (amitriptyline, nortriptyline) have anticholinergic, sedative, and orthostatic hypotensive effects; trazodone (commonly used as a sleep aid) causes significant sedation and orthostatic hypotension. Age-related pharmacokinetic changes in the elderly compound these risks: reduced renal clearance (lower GFR), decreased hepatic metabolism (reduced CYP450 activity), increased body fat ratio (prolonging action of lipophilic drugs), decreased albumin (increasing free drug levels of protein-bound drugs), and increased blood-brain barrier permeability (enhanced CNS effects).

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Diagnosis & workup

Diagnostics & workup: - Comprehensive medication reconciliation with FRID identification: systematically review ALL medications (prescription, OTC, herbal, supplements) and classify each by fall-risk mechanism (sedation, orthostatic hypotension, anticholinergic effects, electrolyte disturbance); include PRN medications that may be used intermittently - Beers Criteria assessment: apply the American Geriatrics Society Beers Criteria to identify potentially inappropriate medications in patients ≥65 years; categories include medications to AVOID (e.g., benzodiazepines, first-generation antihistamines), medications to use with CAUTION, and drug-drug interactions to avoid in older adults - STOPP/START criteria application: Screening Tool of Older Persons' Prescriptions (STOPP) identifies potentially inappropriate prescriptions; Screening Tool to Alert to Right Treatment (START) identifies beneficial medications that are inappropriately omitted; more sensitive than Beers Criteria for detecting adverse drug events in European/international populations - Anticholinergic Cognitive Burden (ACB) scale calculation: score each medication as 0 (no anticholinergic activity), 1 (possible anticholinergic activity), 2 (definite anticholinergic activity), or 3 (strong anticholinergic activity); total ACB score ≥3 is associated with significant cognitive impairment and increased fall risk - Orthostatic vital signs before and after medication changes: measure BP and HR supine, then at 1 and 3 minutes standing; particularly important when initiating, titrating, or combining antihypertensives; orthostatic hypotension (systolic drop ≥20 mmHg) is a direct medication-related fall risk factor - Renal function assessment (eGFR using CKD-EPI equation): essential before prescribing or continuing any FRID cleared renally; gabapentin, pregabalin, morphine (active metabolite M6G), digoxin, and many other FRIDs accumulate in renal impairment, amplifying their sedative and adverse effects

Risk factors: - Polypharmacy (≥4 medications): each additional medication increases fall risk by ~14% independent of the specific drugs; polypharmacy also increases the risk of drug-drug interactions that amplify sedative, hypotensive, or anticholinergic effects - Age ≥65 years with age-related pharmacokinetic changes: decreased renal clearance (GFR declines ~1 mL/min/year after age 40), reduced hepatic metabolism, increased body fat percentage (prolongs half-life of lipophilic drugs like diazepam from 20 hours to 100+ hours in elderly), decreased plasma albumin (increases free fraction of protein-bound drugs) - High anticholinergic burden: cumulative anticholinergic effects from multiple medications (each individually may have mild anticholinergic activity) can cause significant cognitive impairment, confusion, and delirium; use the Anticholinergic Cognitive Burden (ACB) scale to quantify total burden - Concurrent use of multiple CNS depressants: combining opioids + benzodiazepines + antipsychotics + sedating antihistamines creates synergistic sedation far exceeding each drug individually; the FDA has issued a Black Box Warning about concurrent opioid-benzodiazepine use - New medication initiation: the first 1-2 weeks after starting any FRID carries the HIGHEST fall risk because the patient has not yet adapted to the drug's effects; this is particularly true for antihypertensives (orthostatic hypotension worst during titration) and sedatives - Renal or hepatic impairment: impaired drug clearance leads to drug accumulation and prolonged effects; many FRIDs (benzodiazepines, opioids, digoxin, gabapentin) require dose adjustment in renal/hepatic impairment; the NP must check eGFR and adjust doses accordingly - Cognitive impairment (baseline dementia or delirium): patients with existing cognitive impairment are MORE susceptible to the cognitive effects of anticholinergic and sedating medications; even 'mild' sedation can significantly impair their already-compromised safety judgment

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