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8/2/2019 Polypharmacy Elderly
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Anna Dabu M.D.University of Western Ontario
June 2009
8/2/2019 Polypharmacy Elderly
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Outline Definition
Epidemiology
Drug response and pharmokinetics in the elderly Rational drug use in the elderly
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Definition
No standard definition for “polypharmacy ”
“Unnecessary use” vs. absolute number of medications
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EpidemiologyFor those > 65 years of age
44% of men and 57% of women use ≥5 medications/ wk
12% both genders ≥ 10 meds/wk
1059 rural community-dwelling patients (mean age 74.5 years)
50% took 2-4 over the counter medications
2590 noninstitutionalized patients
47% and 59% took a vitamin or mineral
11% and 14% took herbal supplements
Inappropriate drug use in up to 40% of nursing homepatients!
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Adverse Drug Events 10% of ER visits
10-17% of hospital admissions
Commonly: electrolyte, renal, gastrointestinal tract,hemorrhagic and endocrine abnormalities
Others: prolongation of QT interval: f luoxetine andamitriptyline
RF for polypharmacy: age, multiple health care providers,increased co-morbidities, institutionalization, low socio-economic status, dementia
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Drug response in the elderly• Increased sensitivity to drugs
Barbiturates, opiods, cyclic antidepressants,benzodiazepines, central alpha-agonists
Increased sensitivity to changes in thermoregulationcaused by drugs Phenothiazines, anticholinergics
Decreased sensitivity of baroreceptors resulting inincreased risk of postural hypotension Phenothiazines, nitroglycerin, nifedipine, prazosin, diuretics
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Drug absorption and distribution in
the elderly ↑ risk of harm:
GI motility opiods and antihistamines
∆ in fat: lean body mass Increased [ ] morphine, lithium, levodopa, digoxin, acebutolol
Lower plasma albumin
Decreased protein binding
Sulfonylureas, warfarin
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Drug metabolism in the elderly ↓ phase I metabolism (oxidation and reduction)
Altered first-pass metabolism
Propranolol, verapamil, nifedipine
Induction or inhibition of cytochrome p450
Inhibitors of 3A4: nefazodone, ciprofloxacin, norfloxacin, ketoconazole,erythromycin
Metabolized by 3A4: amitriptyline, doxepin, benzodiazepines, hydrocodone,amiodarone
∆ in renal function (drug elimination) Altered renal clearance
Aspirin, digoxin, lithium
Direct alteration in renal function
Lithium intoxication with thiazide diuretic, ACEI, NSAID
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Rational Drug use in the Elderly 1. Beers criteria
1991, 1997, 2002
Expert panel of 13 geriatricians agreed on 18medications/medications classes that should be avoidedbecause either ineffective or high-risk for elderly
Amitritypline, chlorpropamide, disopyramide, doxepine,gastrointestinal antispasmodics, long half-life
benzodiazepines (flurazepam, chlordiazepoxide, diazepam),methyl dopa, sedative or hypnotic agents, petnazocine,meperidine, ticlodipine
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Beers Criteria 4 drug-drug interactions to avoid Specific dosing recommendations:
Digoxin maximum of 0.125mg/day (except rx for atrial
arrythymias) Short-half life benzodiazepines max/day: Alprazolam 2 mg Lorazepam 3 mg Oxazepam 60 mg Temazepam 15 mg Triazolam 0.25 mg Zolpidem 5 mg Ferrous sulfate 325 mg
Warfarin with aspirin/NSAID/dipyridamole/ticlodipine
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Rational Drug Use in the Elderly 2. McLeod et al. Defining inappropriate practices in
prescribing for elderly people: a national consensuspanel CMAJ 1997; 156;385-91
Beers criteria “unacceptable for our purposes”
32 member multi-disciplinary panel developed a list of
71 practices in prescribing for elderly people and ratesthe clinical significance and risk to patient of each,alternative therapies and percent of panel agreeing withalternative
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McLeod et al. 1997 Inappropriate practice of prescribing psychotropic
drugs for elderly people
Discourage prescribing long-half life benzodiazepines totreat insomnia
Clinical signif. 3.72
May cause falls, fractures, confusion, dependence, withdrawal
Non-pharmacologic rx or short-half life benzodiazepine
instead
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McLeod et al, 1997 Inappropriate practice of prescribing NSAIDS and
other analgesics for elderly people
Long-term prescription of NSAIDS to treatosteoarthritis for patients with chronic renal failure
Clin signif. 3.56
may worsen renal failure and cause salt and water retention
Non-drug therapy, acetaminophen
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Summary Polypharmacy in the elderly is not uncommon
Polypharmacy predisposes to increased adverse drugreactions and hospitalizations
Older persons are at increased risk becausephysiological changes in aging result in altered drugresponse and kinetics
Risk factors for polypharmacy are: age, number of
healthcare providers and co-morbidities,institutionalization
Beers Criteria and McLeod (CMAJ 1997) - resources forphysicians
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References Bryan D.H., W. Klein-Schwartz, F. Barrueto. Polypharmacy and the Geriatric Patient.
Clinics in Geriatric Medicine (2007) 23: 371-390
Fick, D.M., J.W. Cooper, W.E. Wade, J.L. Waller, J.R. Maclean, M.H. Beers. Updating theBeers Criteria for Inappropriate Medication Use in Adults. Archives of Internal Medicine
(2003) 163:2716-2724. Hanlon, J.T., L.A.Shrimp, T.P. Semla. Recent Advances in Geriatrics: Drug Related
problems in the Elderly. The Annals of Pharmacotherapy (2000) 34: 360-365
McLeod, P.J., A. Huang, R.M. Tamblyn, D.C. Gayton. Defining Inappropriate Practices inprescribing for elderly people a national consensus panel. CMAJ (1997) 156: 385-391