Polypharmacy: Definition, Causes, and Consequences

Polypharmacy Definition

• Polypharmacy involves the use or misuse of multiple drugs, including prescription and nonprescription medications, alongside their interactions.
• It is generally defined as using at least 5 medications.

Causes

• Multiple prescribers for one patient can cause polypharmacy.
• Treating side effects of one medication with another or fear of ageism accusations are other causes.

Prevalence

• The elderly are the largest consumers of medications.
• Approximately 1/3 of adults aged > 65 who live independently take >5 medications, and nearly 20% take >10.
• 42% of older adults take more than one over-the-counter (OTC) medication.
• 49% take more than one nutritional supplement.

Clinical Consequences

• Polypharmacy is a primary predictor of adverse drug reactions (ADR), which are undesired outcomes from taking medication.
• Adverse drug events (ADE) result in injury from medical intervention related to a drug.
• Other consequences include increased hospitalization, cognitive and functional decline, prescribing cascades, and higher healthcare costs.

Physiologic Changes Affecting Polypharmacy

• Absorption is affected by decreased gastric acidity.
• Distribution is affected by bioavailability, decreased body mass and fluid, decreased cardiac output, increased body fat, and decreased serum albumin.
• Metabolism is impacted by decreased liver mass and function.
• Elimination is affected by decreased renal and hepatic function; kidney function decline begins in the fourth decade of life.

Strategies to Improve Polypharmacy

• Beer's criteria is a list of potentially inappropriate or harmful medications.
• STOPP (Screening Tool of Older Person's Prescription) is a strategy, alongside START (Screening Tool to Alert doctors to the RIGHT Treatment)
• Use the Medication Appropriateness Index Criteria; questions include if there is indication, if the medication is effective, if the dosage is correct/safe, and if directions are practical. The criteria also asks if drug interactions are present, if there is unnecessary duplication, if therapy duration is acceptable, and whether a less expensive alternate is available.

Medications to Avoid (Beers Criteria)

• Anticholinergics (such as 1st gen antihistamines like diphenhydramine, doxylamine, and hydroxyzine), antiparkinson agents
• Anti-infectives like nitrofurantoin
• Dronedarome (Multaq) and Digoxin
• Tricyclic antidepressants
• 1st and 2nd gen antipsychotics such as haloperidol, and benzodiazepines
• Skeletal muscle relaxants
• Non-benzodiazepine sedative hypnotics like zolpidem
• Sulfonylureas
• Sliding scale insulin
• Pain medications, specifically NSAIDs (Indomethacin, Ketoralac); Miperidine
• Proton-pump inhibitors (PPI) for >8 weeks

STOPP Criteria

• Avoid prescribing any drug without evidence-based clinical indication.
• Avoid prescribing any drug beyond the recommended duration.
• Avoid duplicate drug class prescriptions.
• Consider recommendations of medications to avoid, and suggested alternatives, for each system.

Other Strategies in Primary Care

• Implement a "brown bag test," which allows patients to bring all medications for their visit so prescribers may assess for drug interactions, contraindications, and duplications; includes all OTC medications.
• Help patients carry a list of all medications and remind them to update it.
• Be sure to include the caregiver in the review and updatedmedication list.

Take Home Points

• These are lists of medications to consider if the POTENTIAL exists to cause harm.
• The list is a starting point, not a definitive "DO NOT USE" list.
• Weigh risk versus benefit, and assess reason/applicability in patients
• Attempt to consider less risky alternatives if available.

Preventing Adverse Drug Reactions and Interactions

• For the primary disease, choose the safest and most efficient drug, and consider non-pharmacological treatments, if possible.
• Determine drug risk/benefit ratio, and be familiar with sources of drug-interaction information.
• Screen for drug-drug interactions when adding new drugs.
• Evaluate renal function and adapt treatment dosing for impaired function.
• Refrain from adding medications to combat side effects of other drugs.
• Use the fewest possible number of medications, and avoid starting two at once.
• Use drugs that have the simplest administration schedule (ideally once daily).
• Screen patients for self-medications and OTC medication use; eliminate PRN meds unused for >1 month.
• Be sure to provide a medication list for the patient, and evaluate cognitive function.
• Use an interdisciplinary approach to medication management, including family members, caregivers, and pharmacists.
• Ask patients to recite back medication administration instructions.

Polypharmacy is the use of multiple medications, typically five or more. It's caused by multiple prescribers, treating side effects with more drugs, and fear of ageism accusations. This practice increases adverse drug reactions and other negative health outcomes.