Chapter 22: Geriatric patient Flashcards
Incidence of polypharmacy
51% of ages 65-74 use 2+ prescription drugs
12% use 5+
ADRs rate where in causes of death in America
4-6th
Results of advances in medicine for the elderly
prolonged and improved life
increased risk for adverse drug reactions
what are the most common classes of drugs used by the elderly population living in the community
analgesics
diuretics
cardiovascular drugs
sedative hypnotics
what are the most common classes of drugs used by the elderly in nursing homes
antipsychotics and sedative-hypnotics
followed by
diuretics, antihypertensives, analgesics, cardiovascular drugs, and antibiotics
changes in pharmacokinetics related to aging
slowed renal clearance
slowed metabolism
increased risk of CNS side effects
slowed orthostatic response
changes influencing absorptionin the older adult
reduced GI blood flow
reduced gastric acidity
reduced absorptive surface from microvilli atrophy
most drugs are absorbed by passive diffusion
changes influencing distribution in older adults
decrease in total body water and extracellular fluid volume
decrease in cardiac output
decrease in brain and cardiac blood flow
increased total body fat percentage
decrease of total body water in the elderly has what effect on distribution
water-solubla drugs have a reduced volume of distribution which causes increased plasma concentrations of hydrophillic drugs like lithium
what effect does the increase of total body fat in the elderly have on drug distribution
lipohilic drugs have an increased half-life from increased storage in fatty tissue
this can prolong the action of the drug, exacerbate its effect, and increase toxicity
changes influencing metabolism in older adults
reduced CYP450 enzymes impacts the oxidation reaction in phase 1 metabolism
what contributes to a smaller liver reserve than expected for age
the influence of comorbidities, alcohol, medications, and environmental toxins/pollutants
what metabolic changes result in increasing half-life of medications prolonging their availability
ages related reduced hepatic clearance
reduced hepatic blood flow causes reduced first-pass effect
changes influencing excretion in the older adult
reduction in renal mass as well as the number and size of nephrons
reduction in blood flow glomerular filtration rate
reduction in tubular secretion
out of the changes r/t aging that affect pharmacokinetics, which is the most important
changes that influence excretion
cockcroft-gault equation for estimating creatinine clearance
CrCl = (140-age) x (total body weight in kg)
(72) x (serum creatinine in mg/dL)
*result is multiplied by 0.85 in women because of lower muscle mass
changes in pharmacodynamic in the older adult
different effects of a drug on the patient despite identical serum concentrations
what causes the changes in pharmacodynamic in the older adult
altered sensitivyt at receptor site
post-receptor effect
impairment of physiologic and homeostatic mechanism
example of altered receptor sensitivity
increased CNS sedation with benzodiazepines, opioids, neuroleptics
examples of impaired physiologic reserve
more urinary retention and constipation
more blurry vision
increased risk of anticholinergic drugs to glaucoma patients
increased fall risk with sedative hypnotics
examples of some medications that can cause urinary retention d/t anticholinergic effects
antihistamines like:
diphenhydramine (Benadryl)
promethazine (Phenergan)
ipratropium (Atrovent)
prevalence of HTN in older adults
70%
HTN places the elderly at a higher risk for
MI, CHF, CVA, PAD
risk factor for dementia
Is SBP or DBP the primary target for HTN treatment in older adults? why?
SBP because it continues to rise
DBP rises until about age 70, then it begins to fall
drug classes used to treat HTN in the older adult
diuretics
beta-blockers
CCBs
ACE inhibitors
ARBs
alpha blockers
definition of orthostatic hypotension
SBP drop of 20mmHg or more or a drop in DBP of 10mmHg or more
which medication is superior for preventing MI and should be used as first line HTN treatment in older adults
thiazide diuretics
what should be monitored for when an older patient is on a diuretic
hyponatremia, hypokalemia, metabolic alkalosis
beta-blockers in older adults
not first line therapy if uncomplicated HTN
good choice for adjunct therapy with history of HF, MI, or symptomatic coronary disease
Calcium Channel blockers in older adults
2nd or 3rd line treatment for HTN
most common side effect of CCBs in the elderly
peripheral edema that does not respond to diuretics
will resolve with discontinuation of medication
ACE inhibitors
2nd or 3rd line therapy
Avoid with drugs that raise potassium levels
watch for hyperkalemia or worsening renal function
ARBs in older adults
non-peptide selective blocker that is generally well-tolerated
monitor for hyperkalemia
caution with renal insufficiency
alpha blockers in older adults
should NOT be used as 1st or 2nd line therapy
do not use for BPH as there are safer drugs
when should clonodine be avoided for HTN treatment
when there is underlying heart block d/t its bradycardic effect
what does diagnosis of dementia require
losses in multiple cognitive domains as well as functional losses
Alzheimers disese is most common