Drugs in paediatric populations

Question 1

What age is considered a neonate?

Answer 1

0-28 days old

Question 2

What age is considered a infant?

Answer 2

1-12 months old

Question 3

What age is considered a child?

Answer 3

1-12 yrs old

Question 4

What age is considered a adolescent?

Answer 4

12-18 yrs old

Question 5

Absorption: Discuss the gastric pH in neonates and children

Answer 5

Neonates = gastric pH of 6-8, pH drops to 1.5 and 3 (returns to neutral after) in first week of life –> enhanced absorption of acid-labile drugs

Child = by age 2, gastric pH is adult level

Question 6

Absorption: discuss the gastric emptying time of neonates

Answer 6

Neonates and infants = prolonged gastric emptying –> impaired absorption and greater ADR risk

Question 7

Absorption: discuss the peristalsis in neonates

Answer 7

Neonates = irregular and unpredictable peristalsis –> enhanced med absorption

Question 8

How well do neonates absorption intramuscularly?

Answer 8

Variable or delayed in premi and new born

Question 9

Discuss percutaneous absorption in neonates

Answer 9

Enhances skin permeability

Absorption inversely related to thickness of epidermal barrier

Question 10

Discuss rectal absorption in neonates

Answer 10

incomplete and relatively slow

Question 11

Regarding neonates, discuss the drug distribution in relation to body composition

Answer 11

Total body water is higher in infants, neonates, foetus, and children compared to adults

Body fat composition is lower in children

Question 12

Do children require different doses for hydrophilic drugs?

Answer 12

Yes, they have lower body fat

Need higher doses in comparison to adults

Whilst children need lower doses of lipid soluble drugs

Question 13

Discuss how protein binding is influenced in paediatric patients

Answer 13

Binding of drug to plasma protein is dec in neonates

Highly protein bound drugs = less bound in neonates compared to older children –> inc free or unbound drug –> more ADRs/tox

Question 14

How does drug metabolism differ in paediatric patients?

Answer 14

Full hepatic metabolic capacity = 6 months to fully develop

Thus prolonged elimination half life = paracetamol, diazepam, indomethacin, theophylline, phenytoin

Morphine = higher doses in premature infant

WATCH FOR DRUGS W/ SATURABLE KINETICS

Question 14

How does drug excretion would differ in paediatric patients?

Answer 14

Takes several weeks to 1 year for renal function to develop = renally cleared drugs will accumulate in infants

Thus slow elimination of digoxin, aminoglycosides, penicillin, cephalosporins

Question 15

How does hepatic disease affect paediatric therapeutics?

Answer 15

Liver main organ for drug metabolism –> damage or disease –> decreased drug clearance

Cirrhosis and CHF –> dec clearance of drug w/ high extraction ratios

Question 16

How does renal disease affect paediatric therapeutics?

Answer 16

Renal failure = dec dosage requirements of drugs renally excreted

Monitor serum concentrations closely

Question 16

Generally, what factors effect/complicate paediatric pharmacotherapy?

Answer 16

adult concentrations (insulin, morphine, hydralazine, digoxin, atropine, etc.) may need to be diluted

Many drugs need to have altered routes of administration

Drugs will need to be crushed or mixed

Patient may refuse meds

Drug might be lost during administration

Question 16

What factors influence paediatric medication adherence?

Answer 16

Poor communication (parent and med profesh)

insufficient prescribing info

lack of understanding about disease severity

fear of ADRs

failure of patient/parent to administer drug

inconvenient dosing forms

Question 17

What are some common conditions in paediatric patients?

Answer 17

Epilepsy
Cold, cough, fever, nausea
asthma
diabetes
adverse mental health conditions (anxiety, depression, ADHD, sleep disorder, psychosis, OCD, tourette’s)

Question 18

Outline the principle considerations of drug dosing in paediatric patients

Answer 18

Safe = not overdosing

Effective = sufficient to effect a cure/control disease/ relieve symptoms

Measurable = able to measure using tools that are readily available

Question 19

What are exceptions to paediatric dose calculations?

Answer 19

Chemo doses = BSA

Liver, renal, other disorders that affect ADME

> 12 months if above/below average weight = use ideal body weight

Question 20

When can paediatric dose calculations be rounded up?

Answer 20

If wide dose range, TI, max daily dosing

If sub-therapuetic dose is associated w/ ADRs

DONT GO OVER MAX DAILY DOSING

Question 21

When can/should paediatric dose calculations be rounded down?

Answer 21

narrow therapeutic index drugs

Question 22

How can tablets be modified if no liquid formulations are available?

Answer 22

dissolve or be dispersed in water

Check solubility in martindale

Check stability if solution is stored

Question 23

How can injections be modified if no liquid formulations are available?

Answer 23

beware glass fragments

Some vehicles may be harmful

may be in suitable vehicle w. suitable pH