Module 1-2

Question 1

Pregnancy

Answer 1

First trimester is the period of greatest danger
for drug-induced developmental defects
 Drugs cross the placenta by diffusion
 During the last trimester the greatest
percentage of maternally absorbed drug gets to the fetus
FDA pregnancy safety categories

Question 2

Pregnancy Safety Categories

Answer 2

Category A: No risk to human fetus
B: No risk to animal fetus, humans unknown
C: Adverse affects in animal fetus, humans unknown
D: Possible fetal risk in humans, benefit vs. risk may warrant use
X: Fetal abnormalities reported, evidence of fetal risk. Should NOT be used by pregnant women

Question 3

Neonatal and Pediatric
Considerations:
Pharmacokinetics

Answer 3

Absorption
 Gastric pH less acidic
 Gastric emptying is slowed
 Intramuscular absorption faster and irregular

Question 4

Neonatal and Pediatric
Considerations: Pharmacokinetics
(cont’d)

Answer 4

Distribution
 The younger the person, the greater the % of total body water
 Greater TBW means fat content is lower
 Decreased level of protein binding
 Immature blood-brain barrier—more drugs enter the brain

Question 5

Neonatal and Pediatric
Considerations: Pharmacokinetics
(cont’d)

Answer 5

Metabolism
Liver immature, does not produce enough
microsomal enzymes
Older children may have increased metabolism, requiring higher doses than infants

Question 6

Neonatal and Pediatric
Considerations: Pharmacokinetics
(cont’d)

Answer 6

Excretion
 Kidney immaturity affects glomerular filtration rate
and tubular secretion
 Decreased perfusion rate of the kidneys may reduce excretion of drugs

Question 7

Factors Affecting Pediatric Drug

Dosages

Answer 7

Skin is thin and permeable
 Stomach lacks acid to kill bacteria
Lungs have weaker mucus barriers
Body temperatures less well regulated and
dehydration occurs easily
Liver and kidneys are immature, impairing drug metabolism and excretion

Question 8

Dosage Calculation for

Pediatric Patients

Answer 8

Body surface area method
 Using the West nomogram
 Body weight dosage calculations
 Using mg/kg

Question 9

The Elderly:

Pharmacokinetics

Answer 9

Absorption
 Gastric pH less acidic
 Gastric emptying slowed
 Movement through GI tract slowed
 Blood flow to GI tract reduced
 Use of laxatives may accelerate GI motility

Question 10

The Elderly:

Pharmacokinetics (cont’d)

Answer 10

Distribution
 Lower total body water percentages
Increased fat content
 Decreased production of proteins by the liver, resulting in decreased protein binding of drugs (and increased circulation of free drugs)

Question 11

The Elderly:

Pharmacokinetics (cont’d)

Answer 11

Metabolism
Aging liver produces fewer microsomal enzymes, affecting drug metabolism
 Reduced blood flow to the liver

Question 12

The Elderly:

Pharmacokinetics (cont’d)

Answer 12

Excretion
 Decreased glomerular filtration rate
Decreased number of intact nephrons