Pediatrics Part 2 Flashcards by amanda kastel

name 2 main factors that affect drug distribution in children

body composition
protein binding

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explain how body composition and fluid requirements are a concern in children

they can only hold so much liquid – they need a lot that “space” for nutrition

as they grow, they need less and less nutrition and can hold more and more water

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explain the extracellular fluid composition of a neonate/infant and how it changes as they get older

how does this affect the distribution of drugs

when first born, ECF is at highest levels. by 1 y/o, it decreases to 30%

more drug can distribute here and not be effective

IMPACTS DRUG DOSE AND SERUM LEVELS

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explain how the body fat composition changes with age

highest in infancy

affects dosing and serum levels of drugs — they can distribute their and not be effectivie

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name 2 components of body composition that can affect the drug dose and serum level

ECF and body fat composition

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in neonates, there is a ________ Vd than adults

does this mean neonates need a higher or lower dose than adults?

higher

higher dose needed

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name 3 drugs that distribute in ECF and thus ALWAYS need a higher dose than an adult

aminoglycosides
vancomycin
linezolid

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increase concentration of free, unbound drug = ___________ pharmacologic effect

greater

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drugs that are highly protein bound – what can you saw about their therapeutic index?

it is narrow

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how do albumin levels differ in an infant/neonate

they have lower levels/reduced binding capacity and affinity

therefore, there will be higher free concentrations of certain medications

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name 2 plasma proteins that are lower in neonates/infants

albumin
a-1 acid glycoprotein

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when are the adult levels of plasma proteins reached

1 year

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lidocaine:

adults % protein bound = 70%
infant %bound = 20%

how should the infant’s dose be altered

dose must be lowered significantly

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bilirubin is a byproduct of what?

heme catabolism

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explain how bilirubin is a concern in neonates

bilirubin is highly albumin bound

if you give a drug that also is highly albumin bound, the bilirubin may be displaced and enter the brain and cause kernicterus (brain damage, hearing loss)

this is bc bb can’t glucuronidate the bilirubin yet to protect itself - not fully developed phase 2metabolism

DONT USE HIGHLY PROTEIN BOUND DRUG IN A PATIENT WITH A LOT OF BILIRUBIN

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Why do neonates have higher bilirubin levels

because of RBC destruction (byproduct of heme catabolism)
and impaired glucuronication

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give 3 examples of highly protein bound drugs
(thus, they should not be administered to a pt with a high bilirubin level)

ceftriaxone
phenytoin
trimethoprim-sulfamethoxazole

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*** explain metabolism compared to adult:

fetal period
newborn period
early childhood
puberty

fetal period - suppressed metabolism

newborn period - gradual increase in metabolism

early childhood - RAPID METABOLISM — GREATER THAN ADULTS!!! NEED HIGHER DOSE

puberty - metabolism declines to adult levels

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***** true or false

a 4 year old has a faster metabolism than an adult

true

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explain phase 2 metabolism in neonates/infants

when does it mature?

glucuronidation is definitely undeveloped under 1 year. fully develops after a year

HOWEVER, they do have the sulfation pathway of phase 2 metabolism - well developed in infants

method of acetaminophen metabolism

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CYP3A4 metabolizes _____% of all drugs

50%

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**** what is the activity of CYP3A4 at birth?

what % of adult activity is it at by 1 month??

12 months??

VERY LOW activity at birth

30-40% of adult activity by 1 month

by 12 months, IT IS MUCH FASTER THAN ADULTS!!!!!!!!

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TRUE OR FALSE

for drugs metabolized by CYP3A4, young children need higher doses than adults

TRUE

by 12 months they metabolize through CYP3A4 faster

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TRUE OR FALSE

when first born, neonates need higher dosages of drugs that are metabolized by CYP3A4

false - lower doses

very low CYP3A4 activity at birth

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most drugs are ________ eliminated

renally

at what age are adult levels of creatinine clearance reached?

at 6-12 months

below 6 months, what is normal creatinine clearance

it will be much lower than adults - this is normal

what is considered the minimal gestational age for a bb to survive outside the womb? why?

23 weeks bc that's when lungs developed and they can breathe

true or false a less than 6 month old bb with a very low creatinine clearance is most likely in renal failure

FALSE -- this is normal for them a diff eqn must be used for children less than 6 months

by what gestational age is nephrogenesis complete

34-36 weeks

____ is the most commonly used marker for renal assessment in adults and children

serum creatinine

as mentioned, serum creatinine is the most commonly used marker for renal assessment in adults and children name 2 issues with this

kids will have lower serum creatine levels bc of decreased muscle mass and variable glomerular filatration rates not a lot of valid formulas to estimate creatine clearants in infants less than 1 year and neonates

when calculating creatinine clearance for less than 1 year of age, the "L" (length) must be in what units?

cms

when calculating creatinine clearance for less than 1 yr, serum creatinine must be in what units

mg/dL

true or false GFR and creatinine clearance increases as the neonate gets older

true

an adult patient with lower than normal creatinine clearance will get a higher or lower dose?

lower

___________ can change the Vd and clearance

DISEASE STATES!!

at what pediatric weight should be start using adult dosing instead of pediatric

40kg (88 pounds)

true or false growth is linear

FALSE - this is why dosing is challenging birth weight doubles by 6 months and triples by a year, and then slows down

as the child gains weight, the dose has to be ___________

increased

true or false it is never acceptable to round doses

false - may be safe for some medications and age groups, but NOT for others

TRUE OR FALSE growth slows during early childhood and increases during puberty

true

true or false if the child has only increased by 1kg since last dispensed a prescription, dose adjustment is not necessary

FALSE - it absolutely is just 1kg can make a huge dosing difference for peds

_____ is used in dosing certain medications, rather than body weight

BSA (body surface area)

what is IBW and what formula is used to calculate

ideal body weight there is no ideal formula, but can use 50 percentile for age

greater than or equal to what percentile is considered obese? greater than or equal to what percentile is considered overweight?

overweight - greater than or equal to 85th %Ile obese - greater than or equal to 95th %ile

how does obesity affect clearance

larger kidney - may increase GFR and greater frequency of dosing needed -- getting rid of it so quick

in obesity, will there be a higher or lower vd for lipophilic drugs? what about hydrophilic?

higher VD for lipophilic drugs can be higher or lower Vd for hydrophilic drugs

what %ile range is considered "healthy weight" according to the CDC

5-85th percentile

how is metabolism affected by obesity

possible decrease in HEPATIC clearance bc fatty infiltrates increase in phase 1 and 2 reactions

what org gave 40kg as the cut off for stopping pediatroic dosing

the pediatric pharmacy group

in children less than 18 but weigh greater than or equal to 40kg, would you use weight based or adult dosing?

weight based, UNLESS adult dosing will be exceeded

is it acceptable to exceed adult dosing in a pediatric, based on their weight?

NO if exceeds, use adult dosingq

when dosing children, a ___ analysis should be performed whenever possible to provide a more accurate dosing assessment

pharmacokinetic

why is it that there are more med errors in pediatrics than adults

have to calculate dosing, lot of measurement units (lbs->kg) mcg vs mg

trailing zeros and leading zeros

trailing zeros should be AVOIDED leading zeroes should be used --- ie: 0.5 insteas of .5

which should be used -- mL or tsp/tbsp

if a child less than 6 can't swallow sollid dosage forms, what should they be given

liquids

at ______- age, there are AGAIN altered pharmacokinetics

adolescent -- puberty

at what age range is parental and child adherence the best

less than 5

give 2 scenarios in which extemporaneous preparations of PO drugs may be needed in pediatrics

kid can't swallow solids the exact dose isn't available in solid dosage form

true or false capsules and tablets cannot be crushed if they are sustained release or long acting

true

give 4 challenges of IV administration in pediatrics

-may not be done in time - gravity not working to drive into vein -collapsable veins - peds veins easily collapse -limited sites for IV -cooperation from child

what may be needed when giving IV to pediatric patient to ensure the dose is delivered on time

a pump

if a drug is not soluble in water or alcohol and you need a liquid dosage form to give to the child, what should you do? what must the parent be counseled on?

prepare a suspension with suspending agent must be counseled to SHAKE WELL BEFORE USE

Name 5 stability concerns with compounding suspension

physical chemical microbiological therapeutic toxicologic

name an alternative to preparing suspensions for drugs that are insoluble in water and alcohol

crush with powder paper and lactose and have parent administer in jello/apple sauce/ice cream

what is an issue with opening capsules for PO administration

possible uneven drug distribution, lack of stability data

by the age of ______, children can provide and receive info by the age of _______, children tend to be more interested in their healthcare when given the chance

3,7

caregivers who aren't educated about drug administration give liquid medication dose correctly around what % of time

only 50% --- very important to educate just 1-3 mins increases correct dose administration to 95%

true or false as a pharmacist, you should speak to the child in a light and airy tone of voice

false - just talk normally and at or below their eye level

when communicating with a parent, information should be written at what level

6 grade level

what act was made as a result of the sulfanilamide elixir tragedy

1938 FDCA new drugs must be proven SAFE and have adequate directions for use

chloramphenicol in children

does not get converted to the base no glucuronidation pathway -- gray baby syndrome

what is the concern with sulfonamide antibiotics? at what age is this relevant?

less than 2 months - should be used with caution can displace bilirubin from albumin -- bilirubin can cross BBB and cause kernicterus (irreversible brain damage)

TRUE OR FALSE tetracyclines ARE CONTRAINDICATED in less than 8 years of age

true bc calcium chelates with tetracyclines and deposits in kids' bones and teeth causes permanent teeth staining and possible growth retardation from deposition in bone (not permanent - when therapy discontinued it gradually reverses)

Pediatrics Part 2 Flashcards

(77 cards)