Polypharmacy Elderly

8/2/2019 Polypharmacy Elderly

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Anna Dabu M.D.University of Western Ontario

June 2009



Outline Definition

Epidemiology

Drug response and pharmokinetics in the elderly Rational drug use in the elderly



Definition

No standard definition for “polypharmacy ”

“Unnecessary use” vs. absolute number of medications



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!



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



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



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



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



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



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



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



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



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



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



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

Polypharmacy Elderly

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