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