Pharm Quiz Flashcards
USA MCN568 FALL2019
Pharmacokinetics
how drug enter and exits the body, what YOU do to the DRUG
Pharmacokinetics steps
absorption, distribution, metabolism, excretion
absorbtion
drug transfer from site of administration to blood stream
distribution
central circulation to peripheral tissue
metabolism
bio-transformation: converting molecules
excretion
removal
pH changes and drug absorption
low pH (acid) increases absorption of weak acids (furosemide, phenobarbital) high pH (base) increases absorption of weak based, and decrease absorption of weak acid
neonate distribution
body composition: water( 70-75% and fat 15-28% term; protein binding: low albumin concentration, less binding
neonate metabolism
liver- deficiency in enzymes
PHASE I liver metabolism
P450, oxidation, reduction, hydrolysis
PHASE II liver metabolism
conjugation w/sulfate, acetate and glucoronic acid
neonate excretion
kidneys GFR tubular secretion and re-absorption
neonate has: larger volume of distribution, delay excretion, need higher mg/kg dose, longer dosing intervals
bioavailibility
fraction of the administered drug that reaches circulation; IV 100%
half life
is the time it takes for half of the drug to clear the plasma or the time it takes to reduce concentration in half
steady state
concentration of the drug in the maternal circulation that determines the amount of drug available to the fetal compartment; rate of drug administration equals rate of excretion
loading dose
long half life…long time to achieve plateau…larger initial dose
placental transfer of drugs
increase in maternal far, decrease in serum protein, changes in P450 and UGT; placental changes (surface and thickness);
teratogenic
anything external to fetus that causes structural or functional disability in prenatal or postnatal life
pregnancy risk categories DRUGS
A-safe
B-animal safe, no human data
C-animal adverse effect; no human date; benefits outweigh the risk
D human risk; potential benefit outweigh risk
X fetal abnormalities, risk> benefits
AGONIST
activator of the receptor; stimulates response; has affinity and intrinsic activity
ANTAGONIST
inhibitor of receptor, blocks agonist, block response; has affinity but no intrinsic activity
METABOLISM
the rate of drug metabolism is the
primary determinant of both duration and
intensity of drug action
Pharmacodynamics
What DRUGs do to YOU
- Receptors and mechanisms of action
- Stimulators (agonists)
- Blockers (antagonists)
- Dose-response relationships
- Therapeutic effects versus toxic effects
example of teratogenic drugs
thalidomide, valproic acid, carbamazepine, ACE inhibitor, ARBs, tetrecycline, paroxetine, AEDs
neonatal gastric acid production
low at birth
few hours of life pH 1-3
first 10 days of life…near neutral
premature: pH 6-8 first 14 days of life
drug specific factors DISTRIBUTION
molecular size, ionization constant, relative hydrophilic/lipophilic properties; protein bounding
infant specific factors DISTRIBUTION
body composition, membrane/tissue permeability; cardiac output
volume of distribution
Vd: hypothetical fluid volume through which the drug is dispersed
NEONATE Vd
Vd is high/large, lowering max drug concentration, drug clearance is slow…need higher dose
delay drug clearance causes?
prolonged half-life
FAS
greatest single drug-induced cumulative preventable intellectual deficit in children
NAS opioids
clinical presentation: CNS and GI S&S
intubation meds
fentanyl 1-3ug/kg or midazolam 0.1mg/kg
circumcision meds
PO sucrose, acetaminophen, lidocaine block
chest drain meds
fentanyl, local anesthetic, non-pharm measures
ophthalmology exam meds
anesthetic drops, sucrose, containment
post op
police and around the clock, preventative, morphine, fentanyl, acetaminophen
therapeutic drug monitoring
appropriate dosing, modification for desired drug concentrations (t) tau interval, (n) number of doses
peak level
30 minutes post end of infusion
trough level
60 minutes prior next dose administration
NEO meds requiring monitoring
gentamicin, vancomicin, phenobarbital
