Special Populations Flashcards
what occurs to phenytoin as it relates to pregnancy?
spike of phenytoin right after birth
what 5 anatomical and functional changes are increased in pregnancy?
body weight
fat mass
body water
plasma volume
RBC volume
what 3 anatomical and functional changes are decreased in pregnancy?
hematocrit
albumin
alpha-1 acid glycoprotein (AAG)
what 6 physiological changes are increased in pregnancy?
cardiac output
GFR
renal blood flow
creatinine clearance
uterine blood flow
hepatic blood flow
what 3 physiological changes are decreased in pregnancy?
gastric emptying
intestinal motility
acid secretion
why is there a decrease in plasma drug concentration in pregnancy?
increased space and fluid
which hormone in pregnant women is an enzyme inducer, and can then affect drug concentration clearance?
progesterone
which hormone in pregnant women is an enzyme inhibitor, and can then affect drug concentration clearance?
estrogen
what change in pregnancy leads to a prolonged onset of pharmacological effect?
decreased intestinal motility
what can occur during the first trimester of pregnancy due to N/V?
constipation from Al antacids and iron
what causes a pregnant patient to have a faster uptake of anesthetics?
increased cardiac output = hyperventilation = increased alveolar uptake
what causes a pregnant patient to have a decrease in absorption of drugs in the lower extremities?
decreased blood flow to lower extremities in late pregnancy
what causes a pregnant patient to have an increased transdermal absorption of drugs?
increased peripheral vasodilation
what protein is present in the placenta that helps pump out drugs from the placenta?
P glycoprotein
how is it possible that a fetus can be exposed to a drug the mother is taking?
placenta has drug metabolizing enzymes
what 2 factors in drugs allow it to cross the placenta?
lipid solubility
ionization
why do weak bases get trapped in fetal circulation?
fetal pH is lower (more acidic) than maternal pH
which 4 drugs are at risk for becoming trapped in fetal circulation?
meperidine
propranolol
lidocaine
morphine
the fetus has some physiological changes that cause them to be unable to take drugs that have too much protein binding. what is it? (2)
fetus has decreased albumin
fetus has decreased alpha-1 acid glycoprotein (transporter)
why do drugs tend to go directly to the placenta?
increased cardiac output = increased blood flow to uterus
what pumps drugs back into maternal circulation?
placental PgP
during which weeks of gestation are congenital malformations (teratogenesis) at greatest risk?
week 3-11
which 10 drugs are CI in pregnancy?
ACEI
ARBs
ARNI
statins
warfarin
barbiturates
carbamazepine
phenytoin
valproic acid
tetracycline
drug that was initially used as a sedative, anticonvulsant, and managing morning sickness but is a teratogen? what genetic defect?
thalidomide
phocomelia
most human teratogens are also true for _____, BUT reverse is not true
animals
labeling for pregnancy, labor and delivery
8.1
labeling for lactation, including nursing mothers
8.2
labeling for females and males of reproductive potential
8.3
during what trimester is the fetus most sensitive?
first trimester
what is the rule for dosing in pregnant women? (2)
use smallest dose
change dose only when changes have implications
what drugs are used and considered “fetal therapeutics”? (2)
HIV rx
digoxin (fetal tachyarrhythmias)
first 4 weeks (less than 31 days old)
neonate
how many weeks is considered premature?
< 36 week gestation
1-12 months
infant
1-12 years old
children
12-18 years old
adolescent
65 and older
elderly
how are drugs transferred to breast milk?
passive diffusion
what kind of drugs are easily transferred to breast milk? (3)
unionized molecules
unbound
lipid-soluble
avoid taking drugs, if possible, for at least _____ hours before feeding
4
which PK diameter do we think about when feeding an infant right before a dose?
half-life
which 3 drugs have metabolites, which will be present in mother for a longer time?
norfluoxetine (300 hours)
normeperidine (90 hours)
morphine-6G
how is absorption affected in babies? (2)
delayed gastric emptying (PN, N)
increased gastric pH (alkaline)
which 2 ages have delayed gastric emptying?
premature neonate
neonate
which 3 ages have increased gastric pH, making it an alkaline environment?
premature neonate
neonate
infant
what kind of drugs will have an increase in absorption in premature neonates, neonates, and infants? name them
acid-labile drugs
penicillin G
penicillin V
when is percutaneous absorption of drugs increased?
inflamed skin
occlusive dressing
as we move from premature to adult, we lose _____ and start to develop _____
fluid
fat
water-soluble drugs in babies have a _____ volume of distribution
larger
volume of distribution in water-soluble drugs ______ with maturation
decreases
lipid-soluble drugs in babies have a _____ volume of distribution
smaller
volume of distribution in lipid-soluble drugs _____ with maturation
increases
which water-soluble drug has a decreased volume of distribution with age?
gentamicin
which 2 lipid-soluble drugs have an increased volume of distribution with age?
midazolam
diazepam
what 4 levels are decreased in newborns compared to adults?
total protein
albumin
alpha-1 acid glycoprotein
globulin
what 2 levels are decreased in infants compared to adults?
total protein
globulin
what kind of drugs will have a low volume of distribution in newborns?
highly protein bound
at what age do premature neonates and neonates have similar gastric emptying as adults?
6-8 months
at what age do neonates and infants have similar maturity of enzymes as adults?
6 months
why do children have a rapid metabolism of drugs when compared to adults?
liver in children during first 2 years is large in relation to their body size
what is pediatric dosing based on? (2)
weight
body surface area
what are the 2 calculations for child dosing?
Clark’s rule: (child weight/adult weight) x adult dose
Young’s rule > 2 yrs old: (age/age + 12) x adult dose
in an infant, when is GFR the lowest?
first 30 days of life
why is serum creatinine difficult to use as indicator of renal function in infants?
renal function may be worse than serum creatinine since muscle mass is low in infants
