Problems of Polypharmacy Dr Nivi Singh Elderly Care Department
Jan 11, 2016
Problems of Polypharmacy
Dr Nivi Singh
Elderly Care Department
Definition
• Multiple drug use by patients
• 4 or more medications
Elderly
• Medication use increases with age
• Over 60s - 19% of the population
• 57% of dispensed prescriptions
• Over 70s - 20% taking > 5 medications
Causes
• Appropriate
• Inappropriate
Appropriate
• Multiple medical problems
• New drugs for previously untreatable dx
• Proof of efficacy of treatment in elderly
Usually/always Inappropriate
Multiple drug prescribers• Direct relationship btn the number of prescribing
physicians and the incidence of ADRs• Non-medical prescribing
No regular medication review
Prescribing cascade
Prescribing of drugs that are not indicated
Patient factors
• Inaccurate drug history
• Underreporting of symptoms
• Hoarding medications
• Reluctance to discontinue medication
Associations
• Adverse drug reactions
• Reduced compliance - > 2daily doses or >3 different drugs
• Poor quality of life
• High rate of symtomatology
• Hospital admission
• Longer length of stay
Associations
• Increased mortality
• Readmission on discharge
• Drug expense
Adverse Drug Reaction
A response to a drug that is:
noxious and unintended
occurs in doses normally used for the
treatment, prophylaxis, or diagnosis of
disease, or the modification of physiological function (WHO)
ADRs
• Increase morbidity and mortality
• Underestimated
• Implicated in ~17% hospital admissions
• ~30% of elderly pts exposed to drugs that may interact with one another
ADRs
The most consistent risk factor for an ADR is:
Number of drugs being taken
ADR rate 1.2% with 1 drug
10% with 9 drugs
50% with 10 drugs
Mechanisms of altered drug response in the elderly
Changes with age
Altered drug pharmacokinetics• changes in absorption, distribution,
metabolism and excretion
Altered drug pharmacodynamics• altered tissue sensitivity
Volume of Distribution
• Increased % of body fat
• Reduced lean body mass
• Reduced total body water (15%)
Changes in protein binding
Decrease in plasma proteins
• reduced protein bound (inactive) drug • greater amount of free (active) drug • increased drug effect, potentially
resulting in toxicity
Metabolism
• Reduction in hepatic blood-flow and mass
• Hepatic clearance of many drugs is reduced
• Care - drugs with a narrow therapeutic range that are metabolised by the liver (eg. warfarin, phenytoin, theophylline)
Excretion
• Fall in GFR and creatinine clearance
• Reduces elimination of many drugs
• Care - narrow therapeutic range drugs eliminated partially or totally by the kidney (eg. digoxin, lithium and aminoglycoside antibiotics)
Pharmacodynamics
• Changes occur in end-organ responsiveness to medications
• Due to alterations in receptors and homeostatic mechanisms
• e.g. an increased receptor response is seen for benzodiazepines, opiates, and warfarin
• Increased likelihood of an ADR
Drugs that commonly produce adverse effects in elderly
Categories of medication
Medication Category
Cardiovascular
% enrollees
53
Antibiotics 45
Diuretics 30
Opioids 22
Non-opioid analgesics 20
Antidepressants 13
Sedatives and hypnotics
Anticoagulants
13
7
Recognising ADRs
• Constipation• Confusion• Dizziness• Depression• Incontinence• Nausea• Unsteadiness
Falls
Increased risk of falls
• Polypharmacy is a marker of underlying comorbidity
• High risk medications
Benefits of reducing polypharmacy
• Reduced ADRs
• Improved compliance
• Improved patient quality of life
• Reduced hospital admissions
• Lower risk of drug interactions
• Fewer drug errors
• Reduced prescribing costs
NSF
• Gain the max benefit from their medication to increase their quality and duration of life
• Avoid excessive, inappropriate, or inadequate consumption of medicines
Solutions
Basic principles of good prescribing
• Accurate diagnosis
• Non-pharmacological agent
• Start with lowest dose – Start low; Go slow
• Consider potential side-effects and their impact
• Review entire medication regimen
Regular medication review
• >4 medications 6-monthly review
• < 4 medications annual review
• Full drug history
• Over-the-counter medication
• Alternative drug therapies
Alternative drug therapies
• Gingko, garlic and ginseng – all interact with warfarin and possibly aspirin
• Alcohol - exacerbates drug-induced hypotension or sedation
• Many commonly prescribed medications have the potential to interact with alcohol
Medication Review
• Identify unnecessary drugs
• Review dose
• Once daily / once weekly formulations
Medication Review
• Non-pharmacological interventions
• Enlist family/friends as needed
• Medication organisation equipment
• Variety of healthcare professionals
• Information technology
Patient Education
• Written information
• Take drugs as prescribed
• Do not use medication from others
• Report symptoms
• Report all drugs used
Conclusion
• Common and growing problem
• Inappropriate and appropriate prescribing
• Benefits of reducing the drug burden
• Regular medication review
• Not always avoidable –minimise unnecessary multiple drugs