Ped pharm Flashcards
1
Q
Define preterm, neonate, infant, child and adolescent?
A
- preterm: under 36 weeks gestational age
- neonate: first 30 days of life
- infant: 1 month to 1 year
- child: 1 -12 years old
- adolescent: 12-18 years old
2
Q
Variables affect GI absorption of meds?
A
- pH
- gastric emptying time and GI motility
- pancreatic enzyme activity
- GI surface area
- intestinal microorganisms
3
Q
Diff in pH?
A
- more alkaline than adults until child reaches 1
- adversely affects absorption of weakly acid drugs and improves absorption of weakly basic drugs
4
Q
Diff in gastric emptying time and GI motility?
A
- slower than adults for first month of life
- neonates and infants have irregular peristalsis
(can increase absorption)
5
Q
Diff in pancreatic enzyme activity?
A
- decreased for first year of life compared to adults
- affects drugs that are fat soluble (not absorbed)
- neonates can’t absorb vitamin E
6
Q
Diff in GI surface area?
A
- intestinal size relatively to body size matters
- in young kids - relative size of duodenum compared with adults enhances drug absorption
7
Q
Diff in GI microorganisms?
A
- intestinal flora depends more on diet than age
- more rapid development of flora in breast fed infants
- flora is active in breakdown of various drugs
- example: digoxin is reduced to inactive metabolites by anaerobic intestinal bacteria. Digoxin metabolites are not detected in kids until about 16 months of age and adult like reduction of digoxin doesn’t occur until age 9
- warfarin same thing
8
Q
When is rectal absorption used? How are drugs absorbed?
A
- for pts who can’t tolerate oral drugs or lack IV access
- drug is absorbed by hemorrhoidal veins and avoids first pass hepatic metabolism
- most drugs admin by this route are erratically and incompletely absorbed
- ex: Diazepam, valproic acid or secobarbital may be given PR in status epilepticus when lacking IV access
- babies have a lot of BMs, that are unpredictable, and they also don’t have good anal sphincter tone - PR isn’t the best route!
9
Q
IM absorption - what is it affected by? How does it differ in neonates and infants?
A
- affected by muscle mass, blood flow to muscle, tone and activity
- neonates: decreased muscle mass and limited muscle activity decreases blood flow to and from the muscle, erratic and poor drug absorption
- infants: greater density of skeletal muscle capillaries than older children therefore more efficient absorption
10
Q
How is percutaneous absorption affected?
A
- by thickness of the skin
- body surface area relative to body mass
- neonates have thin skin and increased BSA relative to body mass = sig percutaneous drug absorption in neonates compared to adults
- Be careful with ointments and creams!!
11
Q
Factors affecting distribution in ped patients?
A
- vascular perfusion
- body composition
- tissue binding characteristics
- physiochemical properties of the drug
- plasma protein binding
- route of administration
- neonates: these factors are sig different from adults
12
Q
Vascular perfusion in babies?
A
- changes in perfusion are common in neonates
- ex: in response to hypoxia the blood may be diverted (shunted) from the lungs to the tissues and organs
(inhaled meds - low deposition rate in lungs)
13
Q
Body composition in babies?
A
- higher the total body water and extracellular water the larger the volume of distribution
- neonates and infants have increased total body water and ECF compared to older children and adults
- neonates: mostly water, drugs will be more diluted
14
Q
Tissue binding characteristics?
A
- drugs bound to tissue exhibit increased free blood levels when mass of tissue is reduced such as in peds
15
Q
Physiochemical properties?
A
- lipid solubility
- molecular configuration
- these properties affect the ability of the drug to move across membranes into target tissues and cells
- regarding percutaneous absorption, may lead to toxicity in the neonate
