Pharmokinetics
Absorption is influenced by
age, health status, weight and route
Gastric pH
its alkaline at birth; gastric acid secretions reach adults level at 2-3 years so not as effective
Fluid composition in Neonates and Infants
75% water unlike children and adults who have 60% water
More water --> more dilution --> lower drug concentration
What is the key nursing role for peds pharm
monitor the pt for therapeutic effects and adverse rxns (monitor serum drug levels)
Nursing role in drug administration
Provide atraumatic care
Administer drugs based on developmental age
Assess pt's ability to take oral meds
Non-pharmacologic methods during administration
Involve Child Life Specialists
Distribution is influenced by
body composition, protein-binding capability and effectiveness of barriers
Gastric emptying and GI motility
reaches adult fxn by 6-8 mo; gastric emptying is faster in breastfed babies
Protein Receptors
Fewer protein receptors in the first 12 mo--> higher levels of unbound--> increased risk for drug toxicity
Drug dosages for children are ordered based on either the
child's weight in kg or body surface area
SubQ and IM injections
location and no more than how many ml a muscle ?
Vastus lateralis is only place up to 18mo
No more than 1 ml in muscle
Metabolism in children
liver metabolism and higher metabolic rates
Intestinal Surface Area
does not reach adult fxn until 20 weeks and this reduced surface area leads to reduced drug absorption
Free drugs are more likely in infants bc
less protein to bind to drugs
Fried's Rule
Infant dose is age in months divided by 150 and adult dose
Family Centered Collab Care considerations
Ensures safety of administration
Teaching is directed to the primary caregivers
Provide written instructions
Educate regarding the inappropriate use of OTC meds
Excretion in neonates is
decreased
Enzyme fxn
have inadequate production of bile salts and pancreatic enzymes which leads to reduced absorption
Metabolism Considerations
Liver: infants have reduced hepatic blood flow --> toxicity
hepatic blood flow reached adult fxn at 1
Enzymes: drug metabolizing enzymes reach adult level at 11
Clark's rule
child dose= wght in pounds divided by 150 times adult dose
Another example for 4-2-1 Method
Child weighs 52kgs, hourly rate?
(4x10) + (2x10) + (1x32) 32 is whats left after you take 10 away twice;20
which equals 92ml/hr
It is important to check peak and trough because
Drug toxicity is more likely; they metabolize slower and their kidneys aren't mature so drugs aren't excreted as fast
Excretion considerations
Renal excretion is predominant means of drug elimination. GFR is roughly 30% of adults and doesn't reach adult level until 12 mo
GFR is low--> excretion is low--> drug accumulation--> draw peak and trough
Hourly Rate 4-2-1 Method
Say a child is 37.5 lbs. Convert to kg. so 17 kg
(4 x 10) + (2 x 7) + ( 1 x leftover; which in this case its 0)
which is (40) +(14) + (0) = 54ml/hr
So 4ml for the first 10kg
2ml for the second 10kg
1ml for the rest of the kg
times the adult dose