Pediatrics quiz Flashcards
Problem Areas relating to drugs when treating children?
Pharmacokinetics
Pharmacodynamics
Lack of reliable pediatric dosing information
Drug administration
Dosage form alteration
Compliance
Is drug liberation a concern in the pediatric patient?
No
Are membranes hydrophilic or hydrophobic?
hydrophobic
Drugs need to be _________ to dissolve so they can be transported across membranes at the site of action
hydrophillic
How is the pH of of the GI tract affected in a preterm infant?
It’s elevated due to immature acid secretion
What is pH of a full term infant at birth and in 24 hours
pH in full term infant ranges from 6 to 8 at birth and drops to 1-3 within 24 hours
Why will there be elevated levels of penicillin, ampicillin, and nafcillin if administered to a premature infant?
because they are acid-labile and the pH is not as acidic (drug is not degraded as effectively)
Gastric emptying is ________ in the premature infant
slower
Is IM injection reliable in premature infants?
No - small skeletal muscle mass and subcutaneous fat makes IM absorption unreliable
Is IM injection reliable in older infants / small children?
Yes - IM injection effective and usually given in the lateral aspect of a thigh due to insufficient deltoid muscle mass
How is per-cutaneous absorption related to skin thickness and skin hydration?
Inversely related to the thickness of the stratum corneum and directly related to skin hydration
A newborns skin is thinner than an adults, will this result in increased or decreased percutaneous absorption?
increased
A newborns surface area to body weight ratio may be 2-3 times that of an adult, how will that affect percutaneous absorption?
A newborns absorption will be higher
Who will have a higher volume of distribution an infant / small child or adult?
Infant/ small child
What affects protein binding in newborns
Decreased plasma protein concentrations
Lower binding capacity of protein
Decreased affinity of proteins for binding
Competition by substances such as bilirubin
Drug metabolites are catabolized by?
enzymes
Where does most drug metabolism occur
liver
What are the two major metabolic steps in drug metabolism
Oxidation and Conjugation
Phase 1 reactions add?
a polar group to a drug (oxidation)
Phase II reactions involve?
enzymatic coupling of the polar group to an endogenous substance for greater water solubility
Why is drug metabolism slower in infants than adults?
Maturation differences
sulfation pathway well developed but glucuronidation not developed in infants
Metabolic pathway is age related; several months to 1 year to develop
What are the three major enzymes that neonates have difficulty utilizing in drug metabolism
CYP3A4 isoenzyme
CYP1A2
CYP2D6
How do you correct the dosage for a neonate who needs a drug that is broken down by a CYP3A4 isoenzyme?
On average 2-fold increase in weight-corrected doses over adult doses
How do you correct the dosage for a neonate who needs a drug that is broken down by a CYP1A2 isoenzyme?
In neonates cut doses by 50%
How do you correct the dosage for a 2-10 y/o who needs a drug that is broken down by a CYP1A2 isoenzyme?
2-10 years of age need 50% greater weight-corrected dosing
How do you correct the dosage for an adolescent who needs a drug that is broken down by a CYP1A2 isoenzyme?
Adolescents at adult dosing
How do you correct the dosage for a neonate who needs a drug that is broken down by a CYP2D6 isoenzyme?
Neonates need decreases weight-adjusted dosing
all other pediatric patients - no change from adult
Where does drug elimination mainly occur?
through the kidney
Renal clearance is governed by?
Filtration, Secretion, Reabsorption
Whats the most accurate method of drug dosing in pediatrics?
Body surface area (BSA)
What is the most used drug dosing method in peditrics?
Dosing based on body weight.
BSA dosing recommendations not available for most drugs
What are some barriers to compliance with pediatric prescribing?
Poor communication
Insufficient prescribing information
Lack of understanding
Failure to remember to administer the drug
Fear of side effects
Inconvenient dosage forms/dosing schedules
Palatability of dosage forms
What is the current rule that is in effect for pediatric drug testing?
Pediatric Final Rule/Pediatric Research Equity Act
Manufacturer- if you have a drug that has any possible use in pediatric patients you will submit data with your NDA
At what age is a childs GFR up to an adult rate?
About 6 months old
