Ch18: Pharmacology Flashcards
what changes with aging: pharmacodynamics or pharmacokinetics
pharmacokinetics = metabolism, distribution, elimination, absorption
pharmacodynamics knows no age
(4) examples of HIGHLY protein-bound drugs, thus need lower dose in context of aging and low plasma protein
- warfarin (99% bound)
- phenytoin
- valproic acid (Depakote)
- diazepam (Valium)
(4) examples of HIGHLY protein-bound drugs, thus need lower dose in context of aging and low plasma protein
- warfarin (99% bound)
- phenytoin
- valproic acid (Depakote)
- diazepam (Valium)
when compared with a healthy 40-yo adult, CYP450 isoenzyme levels can drop by up to _____% in elders after age 70yo
30%
risks of anticholinergic medications in elderly (5)
- confusion
- urinary retention
- constipation
- visual disturbances
- hypotension
1st-generation antihistamines widely known not to use with older adults (Beers Criteria) d/t systemic anticholinergic effects and reduced clearance (5)
- diphenhydramine (Benadryl)
- chlorpheniramine (Chlor-Trimeton)
- hydroxyzine (Atarax)
- promethazine (Phenergan)
- cyproheptadine (Periactin)
worst OAB medication that has the most systemic anticholinergic side effects
oxybutynin (Ditropan)
if you HAVE to use this for the treatment of OAB, the sustained release is generally better tolerated than the immediate release
be aware that this now comes OTC as “Oxytrol for Women”
discuss which (2) SSRIs are not a good choice for elderly, and which (3) are
BAD CHOICE:
- paroxetine (Paxil), has the most anticholinergic effects and is also the most sedating
- fluoxetine (Prozac) has only a small amount of anticholinergic effects, but is the LONGEST half-life, thus sticks around forever in older adult
GOOD CHOICES: - citalopram (Celexa) - escitalopram (Lexapro) - sertraline (Zoloft) ^^ all of these have NO systemic anticholinergic effects :)
discuss why TCAs are not a good choice for elderly, and which (1) one has the least side effects
most TCAs have very strong anticholinergic effects, sedating, cause hypotension. This is strongest with amitriptyline and nortriptyline
the only one that does not have systemic anticholinergic effects is trazodone, but is still very sedating.
[women vs. men] tend to have higher risk of arrhythmias/ QT prolongation / torsades de pointes with macrolide antibiotics (erythromycin, clarithromycin, azithromycin)
women
never exceed ____mgs per day (adults & elderly) of this SSRI d/t risk for QT prolongation
40mg of citalopram (Celexa)
do not exceed 20mg in elders >60yo
which SSRI has risk of QT prolongation
citalopram (Celexa)
higher risk of QT prolongation in someone taking citalopram (SSRI) and these GI medication….
PPIs (all)
cimetidine (Tagamet), an H2 blocker, but ranitidine and famotidine do NOT have this risk!! better choices
does escitalopram have risk for QT prolongation?
No :)
safer than citalopram in this regard
prescribing principle: drugs with a [shorter vs. longer] half life tend to be better choices for elderly adults
shorter half-life = better choice
elderly adults tend to have reduced metabolism and clearance of drugs, thus the effects hang around longer