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26 Cards in this Set
- Front
- Back
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what are the three ways that you need to do to evaluate benefits which can be used to determine risk/benefit ratio
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comprehensive geriatric assessment (CGA), life expectancy (e.g. drug may take longer than their life expectancy - look at gap between control and experimental lines), prioritize outcomes (ask the patient what he wants)
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what is the comprehensive geriatric assessment
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whole bunch of assessments used to determine things like functional status, dementia, pain, polypharmacy, social details
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what is a frail person
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a person with less life expectancy
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how are priorities different between older and young people
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same outcomes but different order of priorities: independence (instituationalization, cognitive function), then money, then death
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what are ADRs
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adverse drug events: reactions that occur at indicated doses (may be unexpected or listed as actual side effects of drugs)
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ADE definition
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any injury resulting from medical intervention related to a drug.
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what are some practical ways of avoiding or decreasing risks
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you look at NUMBER OF MEDICATIONS; specific medications which are potentially inappropriate for older people, look at pharmacodynamics and pharmacokinetics of drugs
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is age the most important risk facor
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no, it is the LEAST important factor. relative age increases but there are some things you are more likely to get when you age. NUMBER of DRUGS is the MOST IMPORTANT RISK FACTOR
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what is the best definition of polypharmacy
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regimen with at least one unnecessary drug (e.g. you treat the ADR of one drug with another drug)
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ways of avoiding polypharmacy
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Alternatives: nondrug, read a book, warm glass of milk
Vague sx: don’t take medicines for these Duration: stop the first medicine before you start the next one for arthritis if the first didn’t work Therapeutic: do therapeutic before preventative Other MDs: consultants feel like they need to do something |
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what happens to sensitivity to drugs as you get older
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sensitivity to drugs becomes more variable as you get older. (e.g. sedative sensitivity may increase, beta-adrenergic receptor drugs may decrease with age)
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what are some specific ways people's pharmacodynamics change as you get older?
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orthostatic hypotension (ANS changes and decreased baroreceptor function); delirium (centrally acting drugs affect people with dementia); frail patients (diminished reserve capacity ie capacity to take side effects cause no health reserve capacity)
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does drug absorption change a lot when older?
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not significantly affected
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what do you need to consider with albumin
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it declines in sick people. so highly protein bound drugs = higher than expected free drug level (phenytoin, warfarin, NSAIDs); also therapeutic ranges given for dosage may not apply to old people.
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dehydrated patients vs obese patient Vd
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less Vd more Vd. water soluble drugs will distribute less effectively if Vd is decreased = higher plasma concentration = more side effects. fat soluble drugs will have longer half-life if Vd is increased
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what about the liver and the elderly
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assume that hepatic blood flow has decreased with age. If hepatic blood flow is decreased, it may lead to increase systemic bioavailability of the drugs, putting patients at risk for side effects
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what is the main catalyzer of phase I reactions
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cytochrome P450. this ability would be decreased in the elderly.
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what does polypharmacy have to do with induction
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increases the risk that one drug's metabolism enzymes will be induced by the first drug's metabolism enzymes
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what are three things that drug metabolism is affected by enzymes
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inhibited, induced, and genetic influence (e.g. 6 fold difference in CYP metabolism in general population). to evaluate this in a patient make a table with CYP enzymes on y axis, then substrates, inhibitors, substrate side effects, etc. or you can use the GeneMedRx Interactions database
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what about the elderly and drug renal excretion
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it can be variable but generally about 1% lost capacity per year after age 50. but you should go beyong BUN and creatinine as an indication that drug clearance is or isn't affected.
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what is going beyond BUN and creatine levels to determine kidney function
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use Cockcroft-Gault to determine creatine clearance
Cr Cl = (140-age) x weight (kg) / 70 x serum Cr For women, multiply x 0.85 |
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Common drugs excreted by the kidneys
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these are the drugs most affected by renal excretion of drugs.
Digoxin many of the H2 blockers – Atenolol Lithium Many narcotics. |
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what does pharmacogenetics mean for the future.
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Expression of genes may influence Metabolism of drugs, Availability of drugs at their site of action, How drugs bind to their target receptors.
Pharmacogenetics may be used in the future to inform drug choices (responding to drugs and side effects). |
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Pharmacogenetics: CYP2D6 phenotyping studies have shown
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some people are slow metabolizers of this enzyme which some cardiovascular drugs, psychoactive drugs and morphine derivatives are CYP2D6 substrates. therefore avoid these drugs to avoid ADRs and ADEs
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APO E2 and E4 polymorphisms
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E2 polymorphism may have a better lipid-lowering response to statin therapy compared to people who are APO E4.
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what are the drugs that we should avoid in the elderly
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Darvon (analgesic), indomethacin (NSAID that causes CNS effects), muscle relaxants and antispasmodics (poorly tolerated in elderly, anticholinergic effects), amitriptyline (antidepressant with anticholinergic and sedation), digoxin (decreased renal clearance), SHORT-ACTING benzodiazepines (sedation and fall risk), demerol (narcotic causes confusion), ketorolac (anti-inflammatory), prozac (only SSRI you should avoid), short acting nifedipine (hypotension), clonidine (CNS side effects)
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