lecture 4. pediatrics

Question 1

Pharmacokinetics: Absorption

Answer 1

Blood flow at the site of absorption (impacts how much med they absorb)
- Heart failure, cardiovascular shock, vasoconstriction
- Changes in peripheral blood circulation

Biochemical and physiological changes in the GI tract
pH
Peristalsis is irregular and slower.
Unpredictable rate of absorption.
Variable rate of gastric emptying.

Question 2

Drug Distribution

Answer 2

Differences in body fat
- 15% in full term neonate –less accumulation of lipid soluble medications
- Lower albumin in neonates – different on protein binding
Neonates have a higher percentage of water than adults
Extracellular is 40% vs 20% in adults
They have an immature blood brain barrier

*15% fat is not that much, the significant difference is the higher amount of water!

Question 3

Drug Metabolism

Answer 3

Metabolizing enzymes are less in neonates.
Slower clearance rates, longer half-lives (because they aren’t pushing as much fluid through the kidneys as we do)
Few studies in infants are available.
Dose-response relationships of some drugs may change markedly during first few weeks after birth.

Question 4

Drug Excretion

Answer 4

Glomerular filtration rate is lower in newborns, 30-40% that of adults.
Excretion is slower.
Increases soon after birth

*lots of this stuff increases shortly after birth (ex., half-lives, blood-brain barrier? etc…)

Question 5

Pediatric Dosage Forms

Answer 5

How will the parent dispense the medication to the child?

ELIXERS: alcoholic solutions that offer consistent dissolution and distribution of drugs (not much alcohol in this)

SUSPENSIONS: contain undissolved drug particles; must be shaken to evenly distribute drug particles (they don’t dissolve, must shake well)

Errors in dosing, 10X (decimal point, ex. giving 0.1 instead of 1.0, which is 10 times less, must know the units and be diligent about it)

Question 6

Pharmacodynamics: Drug administration during lactation

Answer 6

Not all drugs are safe.
Not a high risk but medications do go in breast milk.
Not in the therapeutic range.
Take 1-2 hours before or 3-4 hours after breastfeeding.

Question 7

Pharmacodynamics: Drugs That Produce Pharmacologic Effects in Nursing Infants

Answer 7

Antibiotics (tetracycline) - can affect microbiome of baby
Sedatives and hypnotics (depress CNS and promote sleep)
Heroin and narcotics
Alcohol
Lithium

Question 8

Pharmacodynamics: Pediatric Drug Doses

Answer 8

Based on proportionally reduced adult doses
Based on body surface area, age, or body weight
Most accurate method of dosing is using mg/kg bw (bw = body weight)

*Makes sure you’re in the right spot of the therapeutic zone