801e Polypharmacy Use in Older Adults Flashcards
geriatric syndromes
polypharmacy, dementia, imbalance, functional decline, urinary incontinence, malnutrition, and frailty
medication related problems (MRPs)
untreated indication, med w/out indication, over/under dose, drug allergies, ADRs, drug interactions, non adherence, duplicate therapy
polypharmacy
- administration of many meds together
- 4,5, 9 or more chronic meds
- prescription, OTC, vitamin, supplement, herbal products
consequences of polypharmacy
ADR, inc errors, dec adherence, drug-drug interactions, inc cost, poor outcomes
adverse drug reactions
-elderly 2-3x more likely to have ADR from any 1 drug
prescribing cascade
Prescribing a new drug to treat the side effects of a previously prescribed drug; the symptoms of the first drug may be evaluated as part of the medical problem
changes that can alter drug absorption
- dec in SA of intestinal epithelium
- dec gastric acid secretion
- dec splanchnic blood flow
- delayed gastric emptying
- slowed transit rate
impact on medication absorption
- 1st dose & PRN use (may have delay in absorption)
- chronic use (no change in extent of absorption, no changes in steady state)
- dec absorption of nutrients
altered PK skin absorption
- atropy of dermis and epidermis
- dec tissue blood perfusion
- dec rate of transdermal drug absorption
- variable rate of drug absorption from SC/muscular tissue
- avoid IM injections if possible
absorption of chronic medications given orally to older patients results in…
no changes in stead state level in general
altered PK distribution
- dec lean muscle mass & inc adipose tissue
- inc VD, tissue conc, & half like of fat soluble drugs
- risk of overmedication w/chronic use (inc ADR, lower dose should be used)
fat soluble drugs
diazepam, amiodarone, verapamil, narcotics, antipsychotics
total body water (TBW)
- by age 80, TBW down by 10-15%
- dehydration & diuretic use inc risk of drug toxicity
water soluble drugs
- dec volume of distribution, inc serum drug concentration
- aspirin, lithium, ethanol, ahminoglycosides
drug distribution, tissue concentration, and half life will be increased for which of the following?
lipophilic medications
metabolism of drugs in the elderly
- dec first pass extraction
- dec liver mass
- dec blood flow
- dec liver’s ability to recover from injury
- inc bioavailability
drugs that have high metabolism
atorvastatin, propanolol, simvastatin, verapamil
drugs that have medium metabolism
metoprolol, amiodarone, labetalol, amitriptyline
drugs that have low metabolism
desipramine, imipramine, morphine, diazepam
elimination
- dec renal blood flow
- dec renal mass & functional glomeruli
- dec glomerular filtration rate
- effects of age are variable
serum creatinine
may remain normal despite reduction in creatinine clearance
meds that need renal dosing
allopurinol, digoxin, cimetidine, antibiotics, gabapentin, magnesium products, lithium, meperidine, phenytoin, metformin, atenolol, glyburide, ranitidine, thiazide diuretics, nitrofurantoin
CNS
- inc sensitivity to CNS drugs
- BBB more permeable
- dec dopamine receptors
- inc susceptibility to drug induced delirium
- start low go slow
cardiovascular
- inc risk of QT prolongation & torsades
- inc susceptibility to orthostatic hypotension w/drugs that lower BP
