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Drugs and the elderly.pptx
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- 2. Outline Ageing andaltered drug effects Step wise approach to review medications for elder people Polypharmacy Appropriate prescribing in the elderly Drugs and side effects in the elderly Adverse drug effects Non- Adherence and what to do
- 3. Introduction Optimizing drug therapyis an essential part of caring for an older person Patients aged 60 years and over are the main consumers of drugs because of increased pathology requiring multiple drugs. Ageing alters pharmacokinetics and pharmacodynamics Pharmacological and non- pharmacological factors associated with ageing predispose older persons to an increased risk of adverse drug events
- 4. Age associated mechanisms of altereddrug effects Particular care must be taken in determining drug doses when prescribing for older adults An increased volume of distribution may result from the proportional increase in body fat relative to skeletal muscle with aging Decreased drug clearance may result from the natural decline in renal function with age, even in the absence of renal disease Larger drug storage reservoirs and decreased clearance prolong drug half-lives and lead to increased plasma drug concentrations in older people
- 5. Age associated mechanisms of altereddrug effects Changes in pharmacokinetics and pharmacodynamics Multiple chronic diseases and consequence polypharma Diminished vasomotor regulation and impaired glucose tolerance Hepatic function also declines with advancing age, and age-related changes in hepatic function may account for significant variability in drug metabolism among older adults
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- 7. Drug Absorption There isa decrease in small bowel surface area Decreased active transport Increased GI pH • Decrease in absorption of certain drugs (Antifungals) • Increase in absorption of certain drugs (Nifedipine, (weak acid), Amoxycillin) Slower gastric motility/emptying Increased fat/decreased muscle • Transdermal, IM, SQ Dysphagia may potentially alter absorption
- 8. Drug Distribution Changes inbody composition such as increase in adipose tissue and decrease in total body water and lean body mass Changes result in an increase in volume of distribution of lipid soluble drugs Eg diazepam, verapamil These drugs are excreted at a much slower rate thus prolonging half-life, taking longer to reach steady concentration Water soluble drugs have a decreased volume of distribution, leading to higher plasma concentration Eg digoxin, lithium, cimetidine
- 9. Drug Metabolism Liver isresponsible for drug metabolism and kidney is responsible for excretion Age- related changes lead to decreased liver size, hepatic blood flow and enzyme activity. A decrease in hepatic blood flow prolongs the duration of effect in drugs that undergo first pass metabolism e.g propranolol theophylline nitrates
- 10. Drug excretion Decrease in: •Kidney mass • Nephron size and number • Renal blood flow • Tubular secretion • Glomerular filtration rate • Most drugs are excreted in the kidney and can be measured using the serum creatinine • Therefore, either 24-hour creatinine collection or Crockcroft and Gault equation can be used.
- 11. Excretion cont • Renal excretionof drugs depends on glomerular filtration rate (GFR) • This affects especially drugs that are excreted by 60% by the kidney, such as • ACEI, atenolol, allopurinol, metformin, digoxin, H2 blockers, lithium, etc. • These require dose adjustment and monitoring in the elderly • Toxicity also increases when combining two drugs that compete for renal secretion • E.g., probenicid and penicillin • Serum drug levels may be used to monitor certain drug levels
- 12. Pharmacodynamic Changes: • What thedrug does to the body. • Affected by receptor binding. Pharmacodynamics: • Drug-receptor interactions cause changes in the drug effect. • Receptors function less efficiently • Reduction in the density of beta receptors • Reduction in the parasympathetic control • Reduction in brain receptors • Increase in blood-brain barrier permeability • Decrease in cerebral blood flow • Reduction in homeostatic mechanisms In elderly:
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- 14. Polypharmacy The use ofmultiple medications by a patient Minimum number of medications used to define "polypharmacy" is variable, but generally ranges from 5 to 10 Also consider the number of over-the-counter and herbal/supplements used(ginkgo biloba &warfarin and St Johns Wort& serotonin-reuptake inhibitors) Problematic polypharmacy is defined as the use of multiple medications in a way that is not considered to be appropriate
- 15. Polypharmacy Metabolic changes anddecreased drug clearance associated with aging; this risk is compounded by increasing numbers of drugs used. Prescribing cascades Adherence
- 16. Adverse drug effects Defined asinjury resulting from the use of drug at usual doses. Some drug reactions are idiosyncratic and thus unpredictable, 60-70% occur because of known pharmacological effects. Adverse drug reactions have been estimated to account for 7.9-24% of all hospitalizations of elderly patients.
- 17. Risk factors for ADEin older patients • Age > 85 years • Low body weight or body mass index • >= 6 concurrent chronic diagnoses • Estimated creatinine clearance < 50 ml per minute • >= 9 medications • >= 12 doses of medications per day • A prior adverse drug reaction
- 18. Common presentations of adverse drugeffects in the elderly Confusion: benzodiazepines, phenothiazines Gait disorder: butyrophenones, anticonvulsants Postural hypotension: antihypertensives, diuretics Incontinence: anticholinergic agents Hypothermia: ethanol, tricyclic antidepressants Constipation: anticholinergic agents, verapamil, opioids
- 19. Guidelines for effective prescribing Use Use newdrugs with particular caution Encourage Encourage treatment adherence Treat Treat adequately Start Start low, go slow Know Know the drugs you use Use Use non-drug treatment whenever possible Obtain Obtain a complete drug history
- 20. Questions you should ask before prescribing medicationfor an elderly patient Check Check whether the person is physically able to take the medication correctly Check Check whether the frequency is correct. Check Check whether the dosage is correct Ask Ask which medications the patient is taking including over the counter medications and vitamins.
- 21. Adherence Degree to whicha patient correctly follows medical advise Physical and cognitive impairment is an issue Caregivers/patients need to understand the therapy. Non-compliance is especially poor with long- term medications
- 22. Factors predisposing to non- adherence to treatment Complexityof dosing schedule Frequent changes in medication or brands Multiple medications Unpleasant side- effects Difficult to open containers Cost of medication Difficult routes of administration Inadequate patient education and understanding Cognitive impairment Visual impairment Impairment of physical function
- 23. Handling non- adherence Simplify drug regimens Avoidingpolypharmacy Educate patients and provide carefully written instructions Warning the patient of common adverse drug reactions Performance of cognitive and physical assessments Encouraging face-to-face interview
- 24. Special challenges Doctors shopping andinvolvement of multiple professionals, thus no health care professional takes responsibility for the care of the patients Poor communication between professionals Failure of patients to bring all drugs to every consultation Limited doctor/patient communication Poor patient education Use of both generic and trade names
- 25. Beers criteria • Listof medications considered potentially inappropriate for use in older patients, mostly due to high risk for adverse events. • Medications are grouped into five categories: those potentially inappropriate in most older adults, those that should typically be avoided in older adults with certain conditions, drugs to use with caution, drug-drug interactions, and drug dose adjustment based on kidney function. • Limitation: Drugs used in USA • WEBSITE: https://www.americangeriatrics.org/
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- 27. Common drugs associated withurinary incontinence in older persons
- 28. List of drugs Alcohol α- adrenergicagonists (phenylpropanolamine) α- adrenergic blockers (Prazosin, Doxazosin) ACE-inhibitors(Perindopril, Enalapril maleate) Anticholinergics (Buscopan, metoclopramide, antihistamines, TCA) Caffeine Calcium channel blockers (nifedipine) Loop diuretics (Furosamide) Narcotics (opioids, morphine, tramadol, methadone, pethidine) Cholinergic (neostigmine) Hynotics (BZD midazolam, zolpidem, diazepam, oxazepam)
- 29. Useful tips Document the indicationfor a new drug therapy 1 Educate patients on the benefits and risks associated with the use of a new therapy 2 Maintain a current medication list 3 Document response to therapy 4 Periodically review the ongoing need for a drug therapy 5
Editor's Notes
- #4 Optimizing drug therapy is an essential part of caring for an older person. The process of prescribing a medication is complex and includes: deciding that a drug is indicated, choosing the best drug, determining a dose and schedule appropriate for the patient's physiologic status, monitoring for effectiveness and toxicity, educating the patient about expected side effects, and indications for seeking consultation. Avoidable adverse drug events (ADEs) are the serious consequences of inappropriate drug prescribing. The possibility of an ADE should always be borne in mind when evaluating an older adult individual; any new symptom should be considered drug-related until proven otherwise. Prescribing for older patients presents unique challenges. Premarketing drug trials often exclude geriatric patients and approved doses may not be appropriate for older adults [1]. Many medications need to be used with special caution because of age-related changes in pharmacokinetics (ie, absorption, distribution, metabolism, and excretion) and pharmacodynamics (the physiologic effects of the drug).
- #5 Particular care must be taken in determining drug doses when prescribing for older adults. An increased volume of distribution may result from the proportional increase in body fat relative to skeletal muscle with aging. Decreased drug clearance may result from the natural decline in renal function with age, even in the absence of renal disease [2]. Larger drug storage reservoirs and decreased clearance prolong drug half-lives and lead to increased plasma drug concentrations in older people. As examples, the volume of distribution for diazepam is increased, and the clearance rate for lithium is reduced, in older adults. The same dose of either medication would lead to higher plasma concentrations in an older, compared with younger, patient. Also, from the pharmacodynamic perspective, increasing age may result in an increased sensitivity to the effects of certain drugs, including benzodiazepines [3-6] and opioids [7]. Hepatic function also declines with advancing age, and age-related changes in hepatic function may account for significant variability in drug metabolism among older adults [8]. Especially when polypharmacy is a factor, decreasing hepatic function may lead to adverse drug reactions (ADRs).
- #6 Many medications need to be used with special caution because of age-related changes in pharmacokinetics (ie, absorption, distribution, metabolism, and excretion) and pharmacodynamics (the physiologic effects of the drug).
- #11 24-hour creatinine collection is measured with 24-hour urine collection, is therefore time consuming
- #14 A more systematic approach is required to guide the tailoring of medication regimens to the needs of individuals. One important principle is to match the medication regimen to the patient's condition and goals of care. This includes a careful consideration of the medications that should be discontinued or substituted [34] (table 1). It is particularly important to reconsider medication appropriateness late in life. A model for appropriate prescribing for patients late in life has been proposed [35] (table 2). The process considers the patients’ remaining life expectancy and the goals of care in reviewing the need for existing medications and in making new prescribing decisions. For example, if a patient's life expectancy is short and the goals of care are palliative, then prescribing a prophylactic medication requiring several years to realize a benefit may not be considered appropriate. This is increasingly being recognized as an important consideration when managing individuals with advanced dementia [36]. Additionally, therapeutic medications (eg, antibiotics for pneumonia) may not increase comfort or quality of life when palliative care is the objective [
- #15 Polypharmacy is defined simply as the use of multiple medications by a patient. The precise minimum number of medications used to define "polypharmacy" is variable, but generally ranges from 5 to 10 [21]. While polypharmacy most commonly refers to prescribed medications, it is important to also consider the number of over-the-counter and herbal/supplements used. Problematic polypharmacy is defined as the use of multiple medications in a way that is not considered to be appropriate [22]. The issue of polypharmacy is of particular concern in older people who, compared with younger individuals, tend to have more disease conditions for which therapies are prescribed. It has been estimated that 20 percent of Medicare beneficiaries have five or more chronic conditions and 50 percent receive five or more medications [23]. Among ambulatory older adults with cancer, 84 percent were receiving five or more and 43 percent were receiving 10 or more medications, in one study [24]. The use of greater numbers of drug therapies has been independently associated with an increased risk for an adverse drug event (ADE), irrespective of age [25], and increased risk of hospital admission [26,27]. Polypharmacy has also been associated with decreased physical and cognitive capability, even after adjusting for disease burden [28]. However, it is difficult to eliminate the impact of confounding factors in considering the relationship between polypharmacy and a variety of outcomes in observational studies
- #16 There are multiple reasons why older adults are especially impacted by polypharmacy: ●Older individuals are at greater risk for ADEs due to metabolic changes and decreased drug clearance associated with aging; this risk is compounded by increasing numbers of drugs used. ●Polypharmacy increases the potential for drug-drug interactions and for prescription of potentially inappropriate medications [30]. ●Polypharmacy was an independent risk factor for hip fractures in older adults in one case-control study, although the number of drugs may have been an indicator of higher likelihood of exposure to specific types of drugs associated with falls (eg, central nervous system [CNS]-active drugs) [31]. ●Polypharmacy increases the possibility of "prescribing cascades" [32]. A prescribing cascade develops when an ADE is misinterpreted as a new medical condition and additional drug therapy is then prescribed to treat this medical condition (see 'Prescribing cascades' below). Prescribing cascades are part of the definition of problematic polypharmacy. ●Use of multiple medications can lead to problems with adherence in older adults, especially if compounded by visual or cognitive impairment. A 2017 systematic review of observational studies suggested that drug regimen complexity is associated with medication nonadherence [2
- #17 The possibility of an adverse drug event (ADE) should always be borne in mind when evaluating an older adult; any new symptom should be considered drug-related until proven otherwise. Pharmacokinetic changes lead to increased plasma drug concentrations and pharmacodynamic changes lead to increased drug sensitivity in older adults. (See 'Introduction' above.) ●Clinicians must be alert to the use of herbal and dietary supplements by older patients, who may not volunteer this information and are prone to drug-drug interactions related to these supplements. ADEs result in four times as many hospitalizations in older, compared with younger, adults. Prescribing cascades, drug-drug interactions, and inappropriate drug doses are causes of preventable ADEs. (See 'Adverse drug events' above.) ●ADEs are a particular problem for nursing home residents; atypical antipsychotic medications and warfarin are the most common drugs involved in ADEs in this population
- #20 Various criteria sets exist identifying medications that should not be prescribed, or should be prescribed with great caution, in older adults. However, clinicians need to consider each patient's individual situation, and they should use their best clinical judgment rather than strictly adhere to prescribing guidelines when making prescribing decisions. (See 'Inappropriate medications' above.) ●Clinicians also under-prescribe medications, such as statins, that could provide benefit for older adults. Clinicians may be better at avoiding overprescribing of inappropriate drug therapies than at prescribing indicated drug therapies. Patient financial constraints and unavailability of prescribed doses may contribute to medication underutilization. (See 'Underutilization of appropriate medication' above.)