ped pharm Flashcards
(30 cards)
premature infant
an infant that was born at <37 weeks post conception (gestational age)
Neonate/newborn
0-4 weeks of age
infant
4 weeks to 12 months of age
when does pharmacologic maturation occur?
between 3-6 months of age
what happens during 3-6months of pharmacologic maturation?
rapid physical growth and maturation take place, changing factors involved in UPTAKE, distribution, redistribution, metabolism, and excretion of drugs
T/F: There is no structural difference between infants, children, and adults that affect GI absorption of drugs
True
Difference in the neonate related to gastric ph, gastric emptying, and gastric transit time?
pH (less acidic), gastric emptying and gastric transit time (markedly slower)
Drug distribution
The amount of drug that reaches specific body compartments or tissues (the concentration of drug at the receptor site) is regulated by the distribution process
IV drugs distribution are influenced by
Protein binding, RBC binding, Tissue volumes, Tissue solubility coefficients, Tissue blood flow
The neonate has a _______ and quantitative _______ in protein binding. There is a _____ in the number of plasma proteins and a _____ in the affinity of proteins for drugs in the neonate. This contributes to the apparent _____ volume of distribution in comparison to adult proportions.
qualitative, reduction, decrease, decrease, LARGER
Premature infant (1.5kg) Total body water, extracellular fluid, blood volume, intracellular water, muscle mass, and fat
Total body water-83%,(% body weight ) Extracellular fluid-62%, Blood volume-60mL/kg, Intracellular water-25%, Muscle mass-15% Fat-3%
Full-term infant (3.5kg) total body water, extracellular fluid, blood volume, intracellular water, muscle mass, and fat
TBW-73% ECF-44%, Blood volume-85-105mL/kg, Intracellular water-33% Muscle mass-20%, Fat-12%
Adult (70kg) TBW, ECF, blood volume, intracellular water, muscle mass, fat
TBW-60%, ECF-20%, Blood volume-70mL/kg, Intracellular water-40%, Muscle mass-50% Fat-18%
Infants go through a period of anemia following birth (__-__ months) with the ________ of fetal hgb and the concurrent but slow _______ of RBCs. This is referred to as the physiologic _______ of hemoglobin.
3-6months, destruction, production, physiologic NADIR of hgb (RBC binding)
Total body water, ECF, and blood volume are relatively ______ when comparing the neonate with the child or or adult on a per kg scale. This initial ______ volume of distribution may explain why the neonate requires ______ per kg dose of drugs to reach the desired effect.
larger,
larger,
higher,
(tissue volumes)
The blood brain barrier is ________. _______ soluble drugs diffuse easily. Rate of entry=____ ______. The infant’s _____ receives a large proportion of CO (in comparison to the adult) and the resultant _____ concentration of many drugs is _______ in the infant than in the adult.
Immature, Lipid, Blood flow, Brain, brain, Higher (tissue solubility)
Smaller muscle mass and fat stores (in relation to adults on a per kg basis) provide ____ uptake to inactive sites and tend to keep plasma levels ______. A high proportion of CO is distributed to the vessel rich group-particularly the _____.
less,
higher,
brain
(tissue perfusion)
The ability to metabolize drugs develops to _______ degrees in _______ time period after birth in premature infant and the full term infant. What age is more important in determining maturity of drug metabolism?
Same,
Same,
postnatal age (not gestational age)
ex:baby born at 28wks presents at 3 months.
Hepatic enzymes at birth?
Phase I and II processes development?
Conjugation reactions are developed by?
incompletely developed or absent at birth,
phase 1 and 2 limited but develop a few days after birth.
by 3 months
The ultimate elimination of most drugs or their metabolites is by _____ _______. Drug clearance may be _________ in the neonate. Clearance by most drugs reaches adult values by __ months of age.
renal excretion,
reduced,
3 months
Why is the uptake of inhaled anesthetics more rapid in infants in small children than in adults?
major differences are related to: alveolar ventilation, distribution of CO, body composition, B:G solubility coefficients, tissue solubility coefficients
Tidal volume of infant and adult?
7mL/kg (relatively constant throughout life)
infant alveolar ventilation in relation to FRC vs adult
Va/FRC
5:1 in infants,
1.4:1 in adults
(important)
The infant has ____ muscle mass (on a per kg scale in relation to adults) and a _____ of the proportion of CO perfusing muscle. Distribution of CO is _____ to the vessel-rich group (brain) vs. adults
less,
reduction,
higher
