Intro to Pediatrics - Block 4

Question 1

What are the classifications of a pre-term vs term newborn?

Answer 1

Pre-term: <37 weeks

Term: >37 weeks

Question 2

Classifications of neonates?

Answer 2

Birth - 1 month

Question 3

Classification of Infant?

Answer 3

1 month - 2 yr

Question 4

Classifications of a child?

Answer 4

2-12 YO

Question 5

Classification of adolescent?

Answer 5

12-18 YO

Question 6

Growth charts used from birth to 36 months?

Answer 6

1. Length
2. Weight
3. Head circumference

Question 7

Growth charts use for 2-20 YO?

Answer 7

1. Height
2. Weight
3. BMI

Question 8

Describe the development of neonates and how they get older?

Answer 8

• Babies would lose water weight within the first 7 days of life do to stress and adjustment.
• Birth weight is regained by 10 days, however, if 10% of birth weight that is an indication for dehydration or malnutrition
• Babies have a lot of water and as they age they gain more protein and fat

Question 9

How do vitals differ in neonates than infants and adolescents?

Answer 9

HR: generally higher
RR: generally higher
BP: generally lower

Question 10

What is the difference between PK and PD?

Answer 10

PK: what the body does to the drug (ADME)
PD: What the drug does to the body (Ligand, receptor, tissue)

Question 11

How does the PK change in pediatrics?

Answer 11

ADME varies by age even when normalized by body weight

Question 12

How does PD change in pediatrics?

Answer 12

Differences receptor sensitivity and density

Question 13

PO factors that impact absorption?

Answer 13

1. Gastric pH
2. Gastric motility
3. Bowel length and absorptve area
4. Enzymes and bile salts
5. Microbial flora

Question 14

GI/PO factors that impact absorption in neonates?

Answer 14

Gastric motility and emptying: reduced gastric emptying and poorly coordinated intestinal cotractility
* Adult pattern onset at 6-8 months
* Drug absorption is dependent on disintegration, dissolution, and formulation

Intestinal drug-metaolizing enzymes: Lower
Biliary function and pancreatic enzymes (amylase and lipase): Underdevelopment affects ability to solubilize lipophilic drugs

Question 15

Gastric factors that impact absorption in neonates?

Answer 15

Neonates have higher gastric pH:
* Acid labile drugs are less broken down -> increased F
* Weak acids are neutralized -> decreased bioavailability

Gastric pH will decrease at age 2

Question 16

Rectal factors that impact absorption in neonates?

Answer 16

Increased pulsatile contractions -> decreased holding time

Question 17

Transdermal facotrs that impact absorption in neonates?

Answer 17

Enhanced skin permeability due to:
1. Greater skin hydration
2. Subcutaneous perfusion
3. Increased BSA to mass ratio

Question 18

Intramuscular facotrs that impact absorption in neonates?

Answer 18

Erractic yet effective due to reduced skeletal muscle blood flow and contraction offset by high density of capillaries

Question 19

Gastric pH in neonates (compared to adults)

Answer 19

Increased:
* Decreased F (weak acids)
* Increased F (weak bases)

Question 20

Gastric emptying time in neonates (compared to adults)

Answer 20

Increased delaying absorption

Question 21

CYP3A4 acitivity in neonates (compared to adults)?

Answer 21

Decreased (increased F)

Question 22

GST acitivity in neonates (compared to adults)?

Answer 22

Increased (decreased F)

Question 23

Intestinal drug transporters in neonates (compared to adults)?

Answer 23

Decreased (decreased F)

Question 24

Hydration of epidermis in neonates (compared to adults)?

Answer 24

Increased (increased F)

Question 25

TBW in infants and adults?

Answer 25

**Premature:** 85% **Full term:** 78% **Adults:** 60%

Question 26

ECF volume in infants and adults?

Answer 26

**Premature:** 50% of BW **4-6 month old:** 35% **1 YO:** 25% **Adults:** 19%

Question 27

Plasma protein in neonates?

Answer 27

Decreased plasma protein concnetration Lower binding capcity of protein Decreased affinity of proteins for drug binding Competition for certain binding sites by endogenous compounds

Question 28

Body fat contents in neonates?

Answer 28

Gradually increases as body water decreases

Question 29

What is Vd?

Answer 29

Amount of drug that leaves the plasma into other compartments that dependent on: 1. Hydro or lipophilicity of drug 2. PPB 3. Tissue binding **High:** extensive drug distribution **Low:** drug remain in the plasma

Question 30

Body water and fat ration in neonates (compared to adults)?

Answer 30

Increased: * High Vd (hydrophilic drugs) * Low Vd (lipophilic drug)

Question 31

PPB in neonates (compared to adults)

Answer 31

Decreased (Increased free drug)

Question 32

Describe the distribution of gentamicin in neonates?

Answer 32

Hydrophilic drug and high Vd: requiring more drug to maintain serum concentration

Question 33

What is the difference between Phase 1 and 2?

Answer 33

**Phase 1:** covalent modification of drug to increase polarity (oxidation, reduction, hydrolysis) **Phase 2:** Conjugation of polar groups to increase polarity * Both used to enhance elimination

Question 34

Most important organ for drug metabolisn?

Answer 34

Liver

Question 35

Ezyme activity of neonates?

Answer 35

No CYP development (decreased phase 1) Phase 2: GST activity

Question 36

Hepatic metabolism in neonates (compared to adults?

Answer 36

Slower in neonates and infants than children and adults

Question 37

What are the components of renal clearance?

Answer 37

Glomerular filtration + tubular secretion - tubular reabsorption * Adult GFR reached at 1 yr * Tubular mechanisms take longer than 1 yr to develop

Question 38

How do we calculate eGFR?

Answer 38

Question 39

Renal excretion in neonates (compared to adults)?

Answer 39

Question 40

Dosage adustment based on elimination (neonates)?

Answer 40

**Decreased elimination:** decreased dose and increased intervals **Increased elimination:** increased dose and decreased intervals

Question 41

How would you dose pediatrics?

Answer 41

Predominately in children less than 2 YO * doses normalized by body weight or BSA and allometric scaling is used in >2YO