11. Pediatrics

Question 1

ontogeny

Answer 1

development

need a fundamental understanding of the role of ontogeny in the disposition and action of drugs

Question 2

neonate

Answer 2

birth to less than 1 month

term neonate: born at a gestational age of at least 37 weeks

premature neonate: born at a gestational age of less than 37 weeks

Question 3

infant

Answer 3

1 month to less than 1 year

Question 4

child

Answer 4

1-12 years

Question 5

adolescent

Answer 5

13-18 years

Question 6

limited data on drug safety and efficacy

Answer 6

20-40% of drugs have FDA approved labeling, most drugs used off label for children

do not have sufficent research due to:

ethical issues
difficulties recruiting
challenges with consent/assent(children give OK)
not as profitable
need for pediatric infastructure

Question 7

Pharmacokinetics

Answer 7

what body does to drug: different in kids

Question 8

GI absorption

Answer 8

slower gastric emptying in neonates/infants:

therapeutic effects may be delayed
more efficient absorption

higher gastric pH in neonates/infants due to immature acid secretion

higher plasma concentration of acid-labile drugs(penicillin)
will not break down as readily - more drug makes it to the small intestine

Question 9

skin absorption

Answer 9

percutaneous drug absorption is increased in children (especially neonates/infants) due to:

thinner epidermal barrier (stratum corneum)

increased skin perfusion - increased vasculature to skin

ratio of total body surface area to body mass is increased - amount of drug that is absorbed is increased

Question 10

volume of distribution (Vd)

Answer 10

in neonates/infants extracellular and total body water is increased- sacks of water

larger Vd for water-soluble drugs-need for higher dose per unit of body weight to reach therapeutic plasma concentration

Question 11

Plasma protein binding

Answer 11

noenates and infants exhibit decreased plama protein concentration, decreased protein binding capacity and decreased affinity for drug

increase in free fraction of drug - increase pharmacological and adverse drug effects

albumin has lower capacity or afiinity to bind to drugs = increae free fraction of drugs available for action

Question 12

ceftriaxone

Answer 12

can cause kernicterus in neonates

highly protein bound to albuminn in noepnates so displaces bilirubin (endogenous substance)

with excess bilirubin it will cross BBB and cause irreversible neurological damage

Question 13

drug metabolism

Answer 13

slower in noenates and infants compared to other children and adults - takes time for metabolizing enzymes to mature

drug metabolism is faster in pre-pubertal children compared to post-pubertal children and adults

Question 14

renal excretion

Answer 14

process of glomerular filtration and tubular reabsorption and secretion may not fully develop until 1-2 years after birth

neonates and infatnts require lower doses of renally eleminated drugs

premature neonates have signifcantly reduced renal function

young children have increased renal function compared to older children and adults - Creatinine clearance declines over time

Question 15

pharmacodynamic differences in childre

Answer 15

what body does to drug

not as well studied or understood as PK differences

maturational changes in receptor conformation, density, affinity and signal transduction

Question 16

calculations of pediatric doses

Answer 16

DO NOT EXCEED MAX ADULT DOSE

by weight:
mg/kg/day
mg/kg/dose

by body surface area
mg/m2

2.2 lb = 1 kg

Question 17

children require special dosage forms

Answer 17

liquid medications

less then 6 years old unable to swallow solid dosage forms
solutions (evenly mixed) vs suspensions (solid particles must be shaken before use)
exact dose may not be available as tablet

chewable tablets

Question 18

solid dosage form strategies

Answer 18

give in small amount of soft food

ex a tablespoon os yogurt

Question 19

liquid medication form strategies

Answer 19

squirt medication between cheek and gums in 1-2 mL increments - not front of mouth or back of throat

pharmacist can add flavor

alsways use oral syringe

do not add to bottle of milk- may taste bad and now children do not want bottle

Question 20

causes of nonadherence

Answer 20

taste
fear of side effects
caregivers inability to administer drugs in timely manner
caregiver feels medication is unneccesary
confusion between caregivers for who is responsible for dispensing drugs

Question 21

children are at an increase risk of medication errors

Answer 21

most common on prescribing

calulation error, doily dose used vs frequency, appreviations, trailing zeros, dose written as mL instead of mg, failure to recognize max adult dose

dispensing- confused labeling

administration- parents give wrong dose