Geriatric Pharmacotherapy: Managing Older Adults on Multiple Medications Lynne E. Kallenbach, M.D. Asst. Professor of Medicine University of Kansas Medical

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Text of Geriatric Pharmacotherapy: Managing Older Adults on Multiple Medications Lynne E. Kallenbach, M.D....

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  • Geriatric Pharmacotherapy: Managing Older Adults on Multiple Medications Lynne E. Kallenbach, M.D. Asst. Professor of Medicine University of Kansas Medical Center Landon Center on Aging October 5, 2007
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  • Overview What is polypharmacy? What is polypharmacy? Relevant pharmacology Relevant pharmacology Medication use issues with multiple Rxs Medication use issues with multiple Rxs Potentially inappropriate medications Potentially inappropriate medications Approach to modifying medication profiles Approach to modifying medication profiles Quality prescribing Quality prescribing
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  • What is polypharmacy? As older patients move through time, often from physician to physician, they are at increasing risk of accumulating layer upon layer of drug therapy, as a reef accumulates layer upon layer of coral. Jerry Avorn, MD From Gurwitz J. Arch Intern Med Oct 11, 2004
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  • Why Geriatric Pharmacotherapy Is Important Now, people age 65+ are 13% of US population, buy 33% of prescription drugs By 2040, will be 25% of population, will buy 50% of prescription drugs
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  • The Burden of Injuries From Medications ADEs occur in 35% of community-dwelling elderly persons Incidence of ADEs: 26/1000 hospital beds (2.6%)
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  • Adverse Drug Events in Older Adults Serious or fatal ADEs occur in 18.5% of adults aged 55-64 and in 41.9% of adults aged >85 years. Serious or fatal ADEs occur in 18.5% of adults aged 55-64 and in 41.9% of adults aged >85 years. Drug related mortality is the 9th leading cause of death for people >65 years of age. Drug related mortality is the 9th leading cause of death for people >65 years of age. It is estimated that ~30% of ADEs are preventable. It is estimated that ~30% of ADEs are preventable.
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  • Pharmacologic Changes with Aging
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  • Pharmacokinetics Absorption Absorption Distribution Distribution Metabolism Metabolism Excretion Excretion Altered by changes in body make-up Altered by changes in body make-up Decreased lean mass, relatively increased fat
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  • Aging and Absorption Actual amount absorbed not changed Actual amount absorbed not changed Peak concentrations may be altered Peak concentrations may be altered
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  • Effects of Aging on Volume of Distribution body water lower VD for hydrophilic drugs body water lower VD for hydrophilic drugs lean body mass, plasma protein (albumin) higher percentage of drug that is unbound (active) lean body mass, plasma protein (albumin) higher percentage of drug that is unbound (active) fat stores higher VD for lipophilic drugs fat stores higher VD for lipophilic drugs
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  • Aging and Metabolism Metabolic clearance of a drug by the liver Metabolic clearance of a drug by the liver may be reduced because: Aging decreases liver blood flow, size, and mass Aging decreases liver blood flow, size, and mass The liver is the most common site of drug metabolism The liver is the most common site of drug metabolism Phase II pathways generally preferable for older patient Phase II pathways generally preferable for older patient
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  • The Effects of Aging on the Kidney kidney size kidney size renal blood flow renal blood flow number of functioning nephrons number of functioning nephrons renal tubular secretion renal tubular secretion Result: Lower glomerular filtration rate
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  • Serum Creatinine Does Not Reflect Clearance lean body mass lower creatinine production lean body mass lower creatinine productionand glomerular filtration rate (GFR) glomerular filtration rate (GFR) Result: In older persons, serum creatinine stays in normal range, masking change in creatinine clearance (CrCl)
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  • Pharmacodynamics Definition: Time course and intensity of the pharmacologic effect of a drug Definition: Time course and intensity of the pharmacologic effect of a drug May change with aging, eg: May change with aging, eg: Benzodiazepines may cause more sedation and poorer psychomotor performance in older adults. Older patients may experience higher levels of morphine with longer pain relief
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  • Decreased homeostatic reserve Impacts ability to tolerate medications Impacts ability to tolerate medications Postural hypotension Fluid and electrolyte problems Response to hypoglycemia Temperature regulation
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  • Medication Use Issues with Multiple Prescriptions (and OTCsherbalsetc)
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  • General types of medication-related problems Unnecessary drug Unnecessary drug Not prescribing new needed Rx Not prescribing new needed Rx Contraindicated drug Contraindicated drug Dose too low or too high Dose too low or too high Adverse drug event/ drug interaction Adverse drug event/ drug interaction Nonadherence Nonadherence Prescribing cascade Prescribing cascade From Williams CM, Am Fam Phys Nov 15, 2002
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  • Prescribing Cascade Misinterpretation of an adverse drug reaction as a symptom of another condition prescribing of another Rx Misinterpretation of an adverse drug reaction as a symptom of another condition prescribing of another Rx Example: Example: Persons receiving a cholinesterase inhibitor had >50% increase risk for subsequent anticholinergic drug for incontinence Gill et al. Arch Intern Med 2005, April 11
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  • Adverse Drug Events during Care Transitions Med changes between hosp and NH Med changes between hosp and NH Mean # of Rx changed: Mean # of Rx changed: 3.1 from nursing home to hospital 1.4 from hospital to nursing home Most were discontinuations Most were discontinuations ADE attributable to medication changes occurred in 20%; usually occurred after readmission to the NH ADE attributable to medication changes occurred in 20%; usually occurred after readmission to the NH
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  • Characteristics of Older Adults with Medication-related Problems 85 years and older 85 years and older 6 or more active chronic conditions 6 or more active chronic conditions Estimated creat clearance < 50 ml/min Estimated creat clearance < 50 ml/min Low body weight Low body weight Nine or more medications Nine or more medications More than 12 doses of medication daily More than 12 doses of medication daily Previous adverse drug reaction Previous adverse drug reaction From Williams CM, Am Fam Phys 2002, adapted from Fouts, Consult Pharm, 1997
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  • Risk Factors for High Risk for ADE in Older Outpatients from an Expert Consensus Panel Medication Factors Patient factors warfarinpolypharmacy nonselective NSAIDS multiple chronic illnesses anticholinergics prior ADR benzodiazepinesdementia opioids From Hajjar et al. Am J Geriatr Pharmacother 2003, Dec
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  • Drug-Drug Interactions May lead to ADEs May lead to ADEs Likelihood as number of medications Likelihood as number of medications Most common: cardiovascular and psychotropic drugs Most common: cardiovascular and psychotropic drugs
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  • Case A 75 year old woman with hypertension, diabetes mellitus, dyslipidemia, coronary heart disease, congestive heart failure, osteoporosis, arthritis and chronic back pain, depression, and seasonal allergies 75 year old woman with hypertension, diabetes mellitus, dyslipidemia, coronary heart disease, congestive heart failure, osteoporosis, arthritis and chronic back pain, depression, and seasonal allergies
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  • Case A: 15 meds glyburideatenololNSAID pioglitazoneaspirintramadol NPH at hs furosemidesenokot lisinoprilalendronatesertraline HCTZ calcium & vit D loratidine
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  • Case B 85 year old woman with hypertension, dependent edema, dizzy spells, chronic back pain, insomnia, and constipation 85 year old woman with hypertension, dependent edema, dizzy spells, chronic back pain, insomnia, and constipation
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  • Case B: 15 meds HCTZoxycodoneMiralax FelodipineMetamucilindomethacin Furosemide prn Senokotranitidine meclizineColaceambien propoxyphene Exlax OTC trazodone
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  • How many meds is too many? Med count wont distinguish cases A & B Med count wont distinguish cases A & B Med count wont distinguish treatment based on disease-management guidelines from symptom-management meds Med count wont distinguish treatment based on disease-management guidelines from symptom-management meds Wont distinguish prescriber decision- making from patient-generated demand Wont distinguish prescriber decision- making from patient-generated demand Wont distinguish appropriate from inappropriate medication use Wont distinguish appropriate from inappropriate medication use
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  • Manageable Dosing Regimens Manageable number of dosing times/day Manageable number of dosing times/day Once daily formulations if feasible Reduce number of medications that cant be taken at same time as any others Use of reminders, medication box set-up Use of reminders, medication box set-up Feasible to keep track of and filled Feasible to keep track of and filled Affordable so patient does not skip doses to make the supply stretch between refills Affordable so p