Geriatric Pharmacotherapy Flashcards
Geriatric Aging & Medication Impact
general overview
older people = use the most of our meds
older people = aging = difference in bodily functioning
different system age at different rates
age = statistic of an event just increases
frail and weak = increase risk of adverse outcomes
goal = maximize functioin independence and resource match with their needs
changes in body composition with aging
- decrease totaly body water
- decreases lean body mass
- increase body fat
- same or decreases serum albumin
medication impact
- less albumin: more free drug aval = more effect/active
- more body fat = more holding onto fat soulble drugs
cardiovascualr chagnes with aging and drug effect
- decrease myocardial sensitivty to beta-adrenergic stimulation
- decreased baroreceptor activity (changes in BP less dramatic)
- decreased cardiac output
- increased total periphearl resistance
med impact
- decreased flux in BP: need more med to help
- but more responsive to small changes!
CNS changes
endocrine changes
CNS Changes
- decreased volume/weight of brain
- altered cogntion in some aspects
Endocrine Changes
- thyroid atrophy
- increased DM & thyroid disease
- menopaouse (decrease in sex hormones)
GI changes in aging
GU changes
GI Changes
- increased pH gastric
- decrease blood flow (less absorb to circulation
- delayed gastric empting
- slow intestine transit
GU changes
- atroph of vagianl due to decreased estrogen
- BPH due to androgen changes
- age-related incontinence
Immune and Liver Chnages in aging
Immune
- blunted immune resopnse
- decreased cellular immunity = can need more of vaccine to get the proper response
Liver
- decreased size and blood flow
Oral
Pulmonary
changes in elderly
Oral
- changes in dentition
- decreases taste sensation
- less likely to eat because of these
Pulmonary
- decreased max. breathing capacity
- derease total alveolar surface exchange
- decreased respiratory muscle strength
Renal
sensory
skeletal
cahnges with aging
Renal
- decrease nephrons = decrease GFR
- decreased renal blood flow
Sensory
- decreases lens accomodation = farsighted (only see close)
- decrase auditory conduction
- decreased conduction velocity of voice
Skeletal
- decrease bone mass (osteopenia)
Skin/Hair changes in aging
-dry skin & wrinkling
- cahnges in pigmentation
- epithelial loss, dermal thicness loss
- decrease follicles
- decreased melanocytes
how does pharmacodynamics change in aging
- GI absorbtion
- distribution (plasma and fat)
GI Absorbtion
- there is no change in passive diffusion process
- thus, no change in bioavalibilty of meds
- might take longer to diffuse, but same amoutn will
- there is change in active diffusion (like B12 and intrinsic factor)
Distribution
- theres less water: so a decreased volume of distribution and increased plasma concentration of drugs that are water soluable (more in the plasma becasue less water for it to diffuse throughout)
- there is more fat: so a increase in volume of distribution of fat soluable drugs meaning longer 1/2 life for these fat-solubale drugs takes longer for them to seep back out of teh fat into the blood since theres so much fat
Hepatic Metabolisma and Renal Excretion in Elderl of Medications
how does clearnace and 1/2 life of drug change based on these parameters
Hepatic Metabolism
- for drugs which are oxidatively metabolized: there is a decreased clearance ability and therefore an increased 1/2life for these drugs since there is less working liver to do this
- for drugs which usually get a lot of elimination through first pass, we dont see this in elderly: so there is decreased clearance and therefore increased biavalibilty of these meds since the liver works less (less first pass effect)
Renal Excretion
- decreased clearance ability and therefore increased 1/2life of drugs which are renally eliminated
how are pharmacodynamics changed in elderly? how are pharmacokinetics?
Pharmacodynamics: what drug does to body
pharmacokinetics: what body does to drug
kinetics: we saw with liver, renal, fat and water changes
Pharmacodynamics
- elderly have altered sensitivites to drugs
- may have different receptor numbers (increased or decreased affinity for specific drugs)
Increased sensitivity to
- benzos
- anticoags.
- antipsychotics
- sedatives
- narcotics
Decreased sensitivity to
- betaadrenertic agonists and antagonists
- vasodilators
goals of geri. pharmacology
probelms and risk facotrs in geri pharm
scales to determine proper Rx in elderly
Goals
- maintain independence
- prevent disability
- increased health-related QOL
Problems in Geri Pharm
- withdrawal from drugs can be big
- ADR can be more pronounced
- therapeudic failure
- Overuse (polypharm)
- inappropriate (too little, too much) BEERS meds
Tools to use
- Medication Appropriateness Index
- Beer’s List
what are the 4 biggest BEERS list medications
others to avoid
- FIRST GEN antihistamines (anticolenergics overall)
- avoid these!!! unless severe anaphlayxis: then can use diphenhydramine
- will created anticholengeric effects: dry mouth,urinary retention, confusion, constipation - Antithrombotics (dipyridamole)
- avoid becuase of orthostatic risk - Centrally acting alpha agonists (clonidine)
- avoid as first line HTN treatment: because these are periphearlly acting: dilated and increase hypotension
OTHERS
- TCAs (anticholenergic)
- antipsychotics (dementia risk)
- analgeics (NSAIDS because GI bleed risk)
- meperidine
- skeletal muscle reactants (sedation and anticholenergic)
Pearls for Geriatirc Pharmacy
- always assume symptoms are a medication related issue during ddx.
- simplfy regemin as much as possible
- BEERs lista nd STOPP crieris
- titrate: start low go slow
- start 1 med at a time
reveiew meds at every visit (bring them in)
always consider deperscribing
provide written instructions
