Pharmacology

Question 1

Outline the challenges when prescribing in children

Answer 1

• No standard dose as with adults.
• Doses vary with age/weight/body SA.
• Uncertainity regarding allergy status.
• Drugs often used off-licence.
• Differences in physiology affecting drug handling.
• More severe consequences of side effects or drug errors.

Question 2

What are 5 key considerations when prescribing in children?

Answer 2

• What drug?
• What route?
• What dose?
• What form?
• What frequency?

Question 3

Outline the choices of analgesia in children

Answer 3

• Paracetamol (calpol): mild-moderate pain, reduce fever, minimal side effects, dangerous in overdose.
• NSAIDs e.g. ibuprofen: chronic disease with pain and inflammation, troublesome side effects (GI upset), be aware of cautions and contraindications.

Question 4

Which analgesic should never be prescribed in children < 16?

Answer 4

Aspirin - except in Kawasaki disease or when used specifically for its anti-platelet action.
Due to risk of Reye’s syndrome - acute encephalopathy and fatty degeneration of the liver.

Question 5

Outline the analgesic ladder for children

Answer 5

• Mild: paracetamol.
• Moderate: paracetamol + NSAID (e.g. ibuprofen).
• Severe: paracetamol/NSAID + opioid (e.g. morphine).

Question 6

Why is codeine not used in children <12?

Answer 6

As some children quickly metabolise this drug into morphine.

Question 7

List 6 different routes of administration in children

Answer 7

• Oral
• Intravenous
• Intramuscular
• Subcutaneous
• Percutaneous/Topical
• Rectal

Question 8

What is drug absorption affected by?

Answer 8

Gastric emptying, gastric pH, bile acid secretion, bowel length and bowel motility.

Question 9

Do neonates and infants have reduced or increased cytochrome P450 activity?

Answer 9

Reduced

Question 10

What drug form is calpol?

Answer 10

Oral suspension

Question 11

How is the dosing interval of gentamicin determined?

Answer 11

By measuring the peak and trough levels.

Question 12

What affects drug distribution (movement of a drug to/from the blood and bodily tissues)?

Answer 12

• Body composition - total body water.
• Binding proteins.

Question 13

Why should drugs that bind strongly to albumin not be given in neonatal jaundice?

Answer 13

Because the drug may displace bilirubin from protein binding sites and increase the risk of kernicterus.

Question 14

Why do neonates and infant have a reduced GFR?

Answer 14

• Incomplete glomerular development.
• Low renal perfusion pressure.
• Inadequate osmotic load for counter-current effect.

Question 15

What factor influences drug elimination and half life?

Answer 15

GFR