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

Number of drugs being taken 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 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