repro week 5 Flashcards
Topical or Percutaneous absorption in pediatric patients is
enhanced due to what 3 reasons?
- increased skin hydration
- thin stratum corneum
- The ratio of total body surface area-to-total body mass is highest in the youngest group, meaning the relative systemic exposure of topically applied drugs is higher in infants
IV route from drug administration is commonly used in pediatric patients because intramuscular absorption is reduced from what reason?
Reduced blood flow to skeletal muscles and weak contraction in neonate
pH of neonates stomach in the first 24 hours after birth
6-8 (basic)
The pH of a neonates stomach 24-48 hours after birth
1-3 (acidic)
In a pediatric patient, drugs that are weak bases in a basic environment (right after birth) exist in what form?
Non-ionized and can cross the plasma membrane
Easily absorbed
Weakly acidic drugs in a basic environment (immediately after birth), will exist in what form?
Ionized form
Not Absorbed
breast fed infants empty their stomach ________ as fast as formula fed infants
twice
Benefit: less drug absorption = less chance for toxicity
Gastric motility is _________ in premeies. Important consideration in dosing due to _________ drug absorption
slower
increased
Inhalation drugs in infants and older children through the pulmonary route has what major advantage?
Advantage – avoidance of systemic exposure
At birth, what is immediately give via intramuscular route that takes advantage of the slow release and decreased clearance to allow for longer effects?
Vitamin K
Infants have a __________ total body water and extracellular fluid than children or adolescents
higher
Infants have a higher volume distribution on water soluble drugs, this means you have to do what to a neonates dose to achieve a therapeutic effect of a water soluble drug?
Increase the dose to achieve therapeutic serum concentration
e.i., Aminoglycosides (gentamicin and tobramycin)
Lower amounts of adipose tissue in newborns (adipose peaks at 4-6 month) causes what effect to the volume distribution of fat soluble drugs?
The amount of body fat is SUBSTANTIALLY lower•Lower volume of distribution of fat-soluble drugs
The amount of body fat is SUBSTANTIALLY lower causes Lower volume of distribution of fat-soluble drugs
Sulphonamides displaces bilirubin from its binding sites in infants and results in deposition in the brain causing what severe complication?
kernicterus - unconjugated (indirect) bilirubin accumulates in the brain
Newborns and infants have ________ amounts of plasma proteins causing more free drugs available in the blood.
Lower
In neonates, Vancomycin and phenobarbital may achieve higher concentration in CNS due to what main reason?
immature BBB.
Phase I and II reactions are slower at birth in full-term infants
Preterm babies have _________ hepatic enzymes
Different timelines for different enzymes to mature
delayed
What condition is associated with chloramphenicol administration in babies (used now as a “last resort” antibiotic b/c of various toxicities)
It is a rare but life-threatening condition in infant and premature babies where Uridine diphosphate-glycuronosyl transferase is not well developed. Due to the low GFR it cannot be eliminated causing an accumulation of toxic metabolite.
This syndrome usually begins 2–9 days (average of 4 days) after treatment is started.. Symptoms include vomiting, refusal to suck, irregular and rapid respiration, abdominal distention, periods of cyanosis, and passage of loose green stools occur within 24 hours. The children become severely ill by the end of the first day, and in the next 24 hours turn a color and become flaccid and hypothermic
Gray Baby Syndrome
What drug causes mild inhibition of the cytochrome P450 CYP 2D6 enzyme?
Ultra rapid metabolizers (UMs) of this drug have at least three active copies of the CYP2D6 gene and present high metabolic capacity for CYP2D6 substrates (1% to 2% of the population in the US)
Diphenhydramine - Benadryl
What rare condition arises in children and adolescents (2-16 years) and is a complication of influenza B, influenza A and herpesvirus varicella-zoster infections. It is thought to be caused by an acute noninflammatory brain swelling (encephalopathy) associated to the exposure of salicylates (aspirin) during a viral illness has been demonstrated
Reye Syndrome
Newborns have a much lower capacity to excrete drugs due to what?
Newborns have much lower GFR
Infants have a __________ half life of renal excreted drugs compared to adults?
Increased half life - need to administer in intervals to prevent drug accumulation
What are the 3 components of pediatric dosing?
Age (mg/kg/day or mcg/kg/dose)
Weight
Surface area
Weight-based dosing in children with BMI> 31 may have suboptimal effects
Scaling adult doses based on body weight or surface area does not account for what, that affects drug disposition or tissue/organ sensitivity.
developmental changes