Elder Meds Part I Flashcards
What is “pharmacokinetics”?
“What the body does with the drug”
What is “pharmacodynamics”?
“What the drug does to the body”
What four things are part of pharmacokinetics?
Absorption
Distribution
Metabolism
Excretion
What are two things that medications can do to receptors?
Blocked
Stimulated
What are some age related changes that affect drug-receptor interaction?
Brain receptors become more sensitive, making psychoactive drugs very potent.
What are some age related changes that affect drug metabolism?
Liver mass shrinks.
Hepatic blood flow and enzyme activity decline.
Metabolism drops to 1/2 to 2/3 the rate of young adults.
Enzymes lose ability to process some drugs, thus prolonging drug half-life.
What are some age related changes that affect drug absorption?
Gastric emptying rate and gastrointestinal motility slow.
Absorption capacity of cells and active transport mechanism decline.
What are some age related changes that affect circulation (in relation to drugs)?
Vascular nerve control is less stable.
Antihypertensives, for example, may overshoot, dropping blood pressure too low.
Digoxin, for example, may slow the heart too much.
What are some age related changes that affect excretion (in relation to drugs)?
In kidneys, renal blood flow, glomerular filtration rate, renal tubular secretion and reabsorption, and number of functional nephrons decline.
Blood flow and waste removal slow.
Age-related changes lengthen half-life for renally excreted drugs.
Oral antibiotic drugs, among others, stay in the body longer.
What are some age related changes that affect distribution of drugs?
Lean body mass falls.
Adipose stores increase.
Total body water declines, raising the concentration of water-soluble drugs, such as digoxin, which can cause heart dysfunction.
Plasma protein diminishes, reducing sites available for protein-bound drugs and raising blood levels of free drug.
What are some drug interactions that slow absorption?
Use of combinations of drugs wherein one drug affects absorption of the other i.e. antacids/Ca/Mg/Al ions bind to object drug decreasing effect of same.
Free fraction effect
Decreased albumin production/aging liver
What is the free fraction effect?
Free fraction effect: drugs binding ++ to protein
Decreased Albumin production/aging liver=rise in free fraction in blood=increase in toxic side effects i.e. malnutrition, uremia; diabetes; acute nephrotic syndrome; surgery
What are the results of slowed liver metabolism?
Aging causes liver function to diminish i.e drug catabolization declines
Active drug or metabolites remain in body longer i.e. long acting benzodiazepines (Diazepam/Valium)
May result in excessive sedation
What rate does creatinine clearance decline with age?
10% every decade after 40 years
What level of creatinine clearance poses a risk of accumulation of drugs/metabolites that are nephrotoxic to kidney function?
Creatinine clearance 30 mL/min or below
What are some important considerations to avoid renal damage from antibiotics? (eg. vancomycin, gentamycin)
Initial renal function level and ongoing Peak and Trough level monitoring essential to prevent irreversible kidney damage /hearing loss/balance disturbances
What is “rational” polypharmacy?
Rational->conscientious, minimal use of multiple drugs +diligent pt. follow-up
What is “irrational” polypharmacy?
Irrational-> inappropriate use of multiple drugs-> risks outweigh benefits
What are some roots of irrational polypharmacy?
Prescriber hesitates to d/c meds. pt. has been taking long time-> adds on more meds
Prescriber orders meds. to alleviate adverse reactions to other meds
Pt. influenced by anecdotal reports re benefits of certain meds
How many patients use alternative pharmacotherapy i.e. herbal remedies unbeknownst to healthcare providers?
40% or more adults
Why do people use alternative pharmacotherapy/herbal remedies without telling their doctor?
Why? Many people believe ‘natural’/alternative medications bought form a reputable source =safe
What are some commonly used examples of alternative pharmacotherapy/herbal remedies?
Commonly used examples: gingseng, ginko biloba,garlic, St. John’s wort however, adverse interactions with some medications ie anticoagulant Warfarin; St. J’s wort/Digoxin level depletion etc.
What is the Beers Criteria? (what is the intention, who is it for?)
Intended for:
use in all ambulatory, acute, institutionalized settings
Adults 65 yrs and older
Palliative and hospice settings excluded
Improve care of older adults by reducing exposure to PIM’s (potentially inappropriate medications)
What are some examples of potentially inappropriate meds (PIMs) and drug-drug interactions in the elderly?
Anticoagulants Anticholinergics Cardiac glycosides Antihypertensive agents Antimicrobials Antipsychotics, anxiolytics, antidepressants, benzodiazepines NSAID’s Laxatives Antacids Long acting oral hypoglycemics Opioid analgesics
