Exam 3- principles of old age pharm Flashcards
(40 cards)
when does pediatric absorption equal adults?
1 year= similar
2 year= acid production is equal to adults
does loading dose change with age?
not really
Cp [mg/L]= DOSE (mg)/Vd (L)
pediatric hepatic metabolism
- function of postnatal age aka very variable compared to adults
- hard to predict
grey baby syndrome
- example of developing hepatic metabolism
- caused by poor clearance of chlorampenicol (delayed development of glucoronidation)
CYP1A2 (phase I)
reach adult llevels are 4-5 mo
cyp2c9(phase I)
> adult levels until teens (<30% at birth)
CYP2D6 (phase I)
reach adult levels by 10 yo
NO activity at birth
CYP3A4 (phase I)
greater than adult levels by 1 year (30%- 75% at birth)
phase II pathyways in the young ones
- sulfate/ glycine conjugation= adult levels at birth
- acetylation= adult levels by 2 years
- glucuronide conjugation= 0-25% at birth –> adult levels by 2-3 years
is renal or hepatic clearance more predictable in kids?
renal
-generally renally cleared drugs are cleared faster in kids than adults
what pharmacokinetic consideration changes a lot with age?
maintenance dose
usu higher in kids than adults
what antibiotic should not be giving to kinds under 9 due to permanent tissue staining? Why?
tetracycline stains teeth.
incorporates into calcifying bone, cartilage, teeth. It is not permanent in tissues that remodel (bone/ cartilage)
things you shouldn’t give to kids due to life threatening reactions
benzonatate iron TCA antipsychotics antimalarials antiarrythmic CCB sulonylureas opiods acetaminophen diphenhydramine
epi of aging and pharm
- 14% over 65
- 20-25% over 65 by 2030
- use 30-40% of prescription drugs
- on multiple chronic meds
- 40% over age 60 take at least 5 meds
- **25% of ED visits/ 40% of hospital stays due to adverse drug events
GI changes in elderly and how it effects meds
- decreased gastric acid (increase pH)
- -decrease weak acid drugs: warfarin, penicillin
- increase weak base drugs: TCA, benzo, opiods, anticonvulsants
take home about absorption in the elderly
RATE is changed with age, but BIOAVAILABILITY doesn’t change much
how does body comp change with aging? how does that change Vd of water soluble/ lipid soluble drugs?
- DECREASE total body water + lean body mass
- –decrease Vd for water soluble drugs –> higher Cp @ nl dose
- INCREASE adipose tissue
- –increase Vd of lipid soluble drugs –> prolonged elimination, drug accumulation
**fat is the only thing that INCREASES, all other tissues decrease in size, production, fx whatever
how does hepatic metabolism change with age? is phase I or phase II affected more?
- decrease mass/ blood flow after age 40
- phase I affected more, decrease 30ish%
- phase II more reliable
- NO GOOD MARKER–> titration necessary
Phase II: Geriatrics have More Gas (methylation, glucoronidation, acetylation, sulfation)
Age is part of the CrCl equation. Yes it is. What are drugs that accumulate with renal impairment?
dig aminoglycosides H2 bockers allopurinol penicillins cephs amantadine lithium metoclopramide
BEERS LIST
use to determine medication use in patients > 65
-but its poorly organized, DDI not addressed, doesn’t consider exceptions (palliation),
STOPP and START screening tools
Screening Tool of Older Person’s potentially inappropriate Prescription
Screening Tool to Alert doctors to Right Treatment
Whats the points of STOPP START screening tools
- red flag areas of POTENTIAL intervention
- STOPP: identifies clinical concerns within a drug class, suggests therapuetic alternatives
- START: suggests appropriate drug use, build from monotherapy
pediatric drug reactions: GCs, CNS stimulants, tets, salicylates
GC –> growth inhibitors via pit GH suppression
Stimulants (ADHD: methylpenidate, dextroampethamine) –> may have growth stunting effect, probably due to app suppresion
Tets –> stain yo teeth
Salicylates (ASA esp) –> risk hepatic dysfx, Reyes
mobility: drugs that effect supporting structures
corticosteroids
phenytoin
heparin
dec vit d
ALL make arthralgis, myopathies, osteoporosis WORSE
