Polypharmacy in Elderly Patients: Managing Multiple Medications Safely

The Polypharmacy Crisis

Polypharmacy — typically defined as taking five or more medications simultaneously — affects approximately 40% of adults over 65 in the United States. Adults 65+ comprise 13% of the population but account for 34% of all prescription medicine expenditures. The average Medicare beneficiary sees 7 different physicians and fills prescriptions at 2+ pharmacies.

This fragmented care creates serious risks:

• Medicine-medicine interactions: Probability of at least one interaction approaches 100% at 7+ medicines
• Adverse medicine events: Leading cause of hospitalization in older adults (20-30% of hospital admissions)
• Falls: Medications are involved in up to 40% of falls
• Cognitive impairment: Anticholinergic and sedating medicines dramatically worsen dementia risk
• Adherence breakdown: Complexity overwhelms patients, leading to dangerous misuse

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Why Elderly Patients Are More Vulnerable

Age-related pharmacokinetic changes significantly alter how medicines behave in older patients:

Altered distribution:

• Body fat increases (25% → 45% of body weight), increasing volume of distribution for fat-soluble medicines (benzodiazepines, opioids) — prolonging their effects
• Total body water decreases — higher concentration of water-soluble medicines (digoxin, gentamicin) for the same dose
• Serum albumin decreases — more free (active) medicine for highly protein-bound medications

Reduced hepatic metabolism:

• Liver mass decreases 20-30%; blood flow decreases 35-40%
• Phase I metabolism (CYP enzymes) reduced; Phase II (glucuronidation) relatively preserved

Reduced renal elimination:

• GFR declines ~1 mL/min/year after age 40
• Many medicines (digoxin, metformin, most antibiotics, NSAIDs) require dose adjustment as GFR falls
• Serum creatinine underestimates renal impairment in elderly (less muscle mass = less creatinine production)

Pharmacodynamic changes:

• Increased brain sensitivity to CNS medicines (opioids, benzodiazepines, anticholinergics)
• Decreased baroreceptor sensitivity → greater orthostatic hypotension risk
• Reduced cardiac reserve → more intolerant of negative inotropes or arrhythmogenic medicines

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The Beers Criteria: Potentially Inappropriate Medications

The American Geriatrics Society Beers Criteria (updated 2023) identifies medications that are potentially inappropriate for adults 65+ due to unfavorable risk-benefit profiles in this population.

Highlighted Beers Criteria medicines:

Benzodiazepines (ALL — short and long-acting):

• Reason: Increased sedation, cognitive impairment, delirium, falls, and fractures in older adults
• Risk is dose-dependent and additive with other CNS depressants
• Alternatives: CBT-I for insomnia; buspirone for anxiety; SSRI for GAD

Anticholinergic medicines:

• First-generation antihistamines: diphenhydramine (Benadryl), hydroxyzine — cause delirium, cognitive impairment, urinary retention
• Tricyclic antidepressants: amitriptyline, nortriptyline — high anticholinergic burden
• Bladder antimuscarinics: oxybutynin especially (mirabegron is preferred alternative)
• Antipsychotics with anticholinergic effects: chlorpromazine

NSAIDs (oral, especially indomethacin):

• Increased GI bleeding risk (especially without PPI co-prescription)
• Worsens hypertension and heart failure
• Acute kidney injury in dehydration
• Alternatives: acetaminophen for most pain; topical NSAIDs for localized joint pain

Muscle relaxants (cyclobenzaprine, methocarbamol, carisoprodol):

• Poorly tolerated: sedation, anticholinergic effects, falls
• Inadequate evidence for efficacy in back pain

Sulfonylureas (especially glibenclamide/glyburide):

• Long-acting; unpredictable hypoglycemia risk (irreversible hypoglycemia reported)
• Prefer shorter-acting glipizide or modern non-hypoglycemia-causing agents (DPP-4 inhibitors, SGLT2 inhibitors)

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Deprescribing: The Art of Stopping Medications

Deprescribing — systematically reducing or stopping medications whose risks outweigh benefits — is one of the most important and underutilized tools in geriatric medicine.

Deprescribing framework (STOPP/START, FORTA):

1. Compile complete medication list (prescriptions + OTC + supplements)
2. For each medicine: What is the indication? Is the indication still present? Was the medicine appropriately monitored?
3. Calculate medicine burden: anticholinergic burden score, CNS medicine count, fall-risk medications
4. Prioritize: Which medications have the highest harm-to-benefit ratio now?
5. Communicate: Involve patient and caregivers in deprescribing decisions; discontinue one medicine at a time with monitoring

Medicines frequently identified for deprescribing in elderly:

• PPIs started during acute illness and never stopped
• Bisphosphonates after >5 years in low-risk patients
• Statins in patients >80 with limited life expectancy or very advanced dementia
• Antihypertensives causing symptomatic hypotension
• Antipsychotics for behavioral symptoms of dementia (should be time-limited trials)