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43 Cards in this Set
- Front
- Back
thiopental crosses the placenta very slowly
T/F |
false
Thiopental crosses the placenta almost immediately can produce sedation / apnea in newborn |
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what kind of drugs tend to diffuse readily acress the placenta and enter the fetal circulation?
|
lipophilic
|
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succinylcholine & tubocurarine cross the placenta slowly
T/F |
true
highly ionized drugs cross slowly and achieve very low conc. in fetus |
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drugs with molecular wt of 250-500 can cross placenta easily
T/F |
true
|
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drugs greater than ___ mol. wt. cross very poorly
|
>1000
250-500 = easy 500-1000 = more difficult >1000 = poorly |
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this transporter pumps drugs back into the maternal circulation and may cause drug accumulation in the fetus
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P-gp encoded by MDR1 gene
|
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protein binding has a greater affect on:
a. poorly lipid-soluble / ionized drugs b. very lipid soluble drugs |
greater affect on A, pooly lipid-soluble / ionized drugs bc they transfer slowly and will be impeded by their binding to maternal plasma proteins
very lipid soluble drugs with NOT be affected greatly by protein binging bc they cross so rapidy |
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what are the roles of the placenta?
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semi-permiable barrier
site of metabolism of some drugs: phenobarbital toxic metabolites of ethanol & benzos |
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drugs that cross placenta enter fetal circulation via ___?
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umbilical v.
40-60% umbilical venous blood flow enters fetal LIVER rest enters general fetal circulation |
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what are some drugs that may be given during preg?
|
maternal drug actions:
cardiac glycosides & diuretics = HF insulin = gestational DM |
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why would you give mother corticosteroids? phenobarbital?
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therapeutic drug action in the fetus: give to mom with fetus as intended target
corticosteroids? stumulate lung phenobarbital? induce fetal hepatic enzymes --> lower incidence of jaundice |
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what is thalidomide?
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a teratogen
single exposure to drug can affect limb developement (4th-7th week) |
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what are some teratogenic mechanisms?
|
- secondary or indirect effect on fetus
- interfere with passage of O2 --> effects on most rapidly metab tissues - processes of differentiation in developing tissues - deficiency of critical substance |
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define teratogen
|
-characteristic set of malformation indicating selectivity for certain tissue organs
- particular stage of developement - dose-dependent incidence |
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fewer than ___ drugs have been identifies as human teratogen for all trimesters
|
30
(just over 40 with teratogenic effects) |
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risk of teratogen?
|
3%
|
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drug absorption in infants and kids can be affected by?
|
blood flow at site of administration
GI fxn |
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blood flow at site of administration changes how with shock, vasoconstriction, HF?
sick, preterm infants? |
these may reduce blood flow, decreasing drug conc.
k, preterm infants have little m mass and diminished peripheral perfusion making absorption irregular and difficult to predicts sudden improvement in perfusion can result in unpredictable increase in amount of drug entering circulation --> high and potentially tox conc |
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GI changes in fxning
|
big changes shortly after birth
gastic emptying time up to 6-8 hrs first day after delivery, meaning drug absorbed mostly in stomach may be more completly absorbed than expected and drugs absorbed in intestine have delayed effect peristalsis in neonate is irregular and may be slow, meaning sm int drugs may be unpredictable, more drug may be absorbed |
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GI enzyme activities tend to be ___ in newborn?
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GI enzyme activities tend to be lower in newborn, may have low conc. of bile acids and lipase with decrease absorption of lipid-sol drugs
|
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which drugs have DECREASED oral absorption?
|
acetaminophen
phenobarbital phenytoin |
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which drugs have NORMAL oral absorption?
|
diazepam
digoxin sulfonamides |
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which drugs have INCREASED oral absorption?
|
ampicillin
penicillin G |
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acetaminophen oral absorption?
|
decreased
|
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what % of neonate body wt is water?
what % extracellular water? |
70-75% TBW
40% extracellular |
|
preterm vs. term body fat %
|
preterm vs. term
1% vs 15% |
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is protein binding in neonate increased or decreased?
|
reduced
|
|
p450 and clearance rates in newborns?
|
lower and slower
also prolonged 1/2 lives |
|
GFR in newborn is what % of adult?
what about toddler? |
30-40% of the adult value--- much lower in newborns
renal elimination drugs are cleared slowly in first weeks of life toddlers increased renal elimination = shorter 1/2 life |
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why would indomethacin be given to neonate?
|
indomethacin
causes rapid closure of patent ductus arteriosus |
|
prostaglandin E1?
side effect? |
PGE1
causes ductus to remain open life-saving in infant with transposition of great vessels or tetralogy of Fallot antral hyperplasia with gastic outlet obstruction as clinical maniestation |
|
what is elixir?
|
elixirs
alcoholic solutions in which drug molecules are dissolved and evenly distributed |
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suspensions?
|
suspensions
contain undissolved particles of drug that must be shaken phenytoin suspensions = uneven distribution potential cause of ineffecacy or tox |
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T/F you can detect almost all drugs mom takes by breast milk
|
true
|
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when should you take a relatively safe drug??
|
30 min after nursing and 3-4 hours before next feeding
|
|
T/F
antibiotics CANNOT be detected in milk |
false
most can |
|
T/F
sedatives and hypnotics conc sufficient to produce effect in some infants |
true
|
|
T/F
nicotine is in milk |
LOW levels
no effects on baby |
|
T/F
caffeine very small effects |
true
|
|
T/F
lithium is undetectable in milk |
false
levels equal to maternal serum! |
|
radioactive substances may increase risk of tyroid cancer
T/F |
true
|
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what is the most adequate measurement to base doses on?
|
surface area
|
|
formulas:
Young's Rule Clarks Rule |
dose = adult dose * (age / age + 12)
dose = adult dose * (wt / 150) |