Pediatric Pharm

Question 1

Drug administration to a pregnant patient can affect the developing fetus in one of two ways

Answer 1

1. Direct fetal effect. Passage into fetal circulation.

2. Indirect fetal effect. Changes in blood flow.

Question 2

How can drugs in material circulation cross the placenta?

Answer 2

1. Passive diffusion (mainly)
2. Facilitated diffusion.
3. Active transport.
4. Pinocytosis/endocytosis

Question 3

Lipid soluble ions passing the placental barrier

Answer 3

Will readily diffuse across.

Question 4

Ionized molecules passing the placental barrier

Answer 4

If they are ionized, they will cross slowly resulting in a very low conc of them throughout fetal circulation. However, this is relative. If the concentration of ionized (polar) drugs in material system is high, they may readily diffuse into fetal circulation.

Question 5

Molecular size and passing the placental barrier

Answer 5

Lower the molecular weight, the more readily the molecule will pass thru placenta. Larger drugs can be transported into fetal circulation.

Question 6

pH and passing the placental barrier

Answer 6

fetal blood is slightly more acidic (7.3) than material blood (7.4). Ion trapping is possible as basic drug can become ionized in acidic fetal circulation.

Question 7

Protein bound drugs passing the placental barrier

Answer 7

Highly bound drugs will have more difficulty passing through the placenta. Exception: Highly lipid-soluble drugs can pass thru.

Question 8

Will maternal or fetal proteins have a higher affinity for drugs?

Answer 8

Maternal proteins have a higher affinity for drugs compared to fetal proteins. This is why dosing adjustments need to be made.

Less protein binding in fetal circulation could result in a greater distribution of the drug since it will be able to travel through capillaries and membranes easier.

Question 9

Can drug effects differ from pregnant female and same female not pregnant?

Answer 9

Yes, but prob not significantly.

Question 10

Examples of drugs a pregnant female may need that are not needed otherwise

Answer 10

Insulin, diuretics.

Question 11

Why might the fetus be a target for therapeutic action?

Answer 11

Ex: Need to mature fetal lungs.

Question 12

perinatal

Answer 12

Weeks before and after birth

Question 13

Predictable toxic drug actions perinatal?

Answer 13

Dependence can develop in the fetus.

Can cause organ damage

Question 14

Teratogenic drug requirements (3)

Answer 14

1. Cause the same defect
2. Occur at the same stage in development
3. Dose-dependent incidence. Specific dose that will cause deformation.

Mechanisms that cause the birth defect are poorly understood. Likely multifactorial.

Question 15

FDA old risk categories

Answer 15

A: No risk in first trimester or later

B: No risk in animal studies, not done in humans.
OR
Adverse effect in animal studies, no confirmation in humans.

C: Give only if benefits outweigh risks. Adverse effect shown in animal studies with no controlled human studies
OR
Studies in women and animals are not available.

D: Life or death situation. Positive evidence of human fetal risk.

X: Fetal abnormalities. Never give to pregnant patient.

Question 16

New FDA rulings

Answer 16

Narrative risk summary replaces A-D and X.
Subsections:
1. Pregnancy. Summary of risk.
2. Breast feeding. Summary of risk.
3. Male and female reproductive systems. Summary of risk.

Question 17

Pharmacodynamic differences are prob not significant in children EXCEPT

Answer 17

Target tissues that mature at birth or shortly after. Ex: lungs.

Question 18

Pharmacokinetic differences in Children: Absorption (2)

Answer 18

1. Blood flow at administration site can be reduced in preterm infants.
2. GI secretion, emptying time, and enzyme activity differ. May require dose adjustments or changes to administration.

Question 19

Pharmacokinetic differences in Children: Distribution (1)

Answer 19

Body water percentage, fat composition, and plasma protein binding are different in infants.

Question 20

Pharmacokinetic differences in Children: Metabolism (1)

Answer 20

Liver enzyme activity is lower in infants. Individual enzymes take different lengths of time to mature.

Question 21

Pharmacokinetic differences in Children: Excretion (1)

Answer 21

Lower glomerular filtration rate in newborns. Higher in toddlers.

Question 22

Percentage of drugs excreted into breast milk?

Answer 22

Concentrations are very small except for antibiotics, sedatives and hypnotics, and opioids

Question 23

Methadone

Answer 23

Medication to help with heroine withdrawal. Opioid that is complicated during pregnancy/breast feeding.

Question 24

Pediatric dose=

Answer 24

Adult dose x (child weight in lbs/150)

Not dependent on age.