Pharmacology and Therapeutic Management
This domain tests safe, weight-based prescribing, dose calculation, monitoring, and stewardship in children.
Core rules
- Most pediatric doses are weight-based (mg/kg/day or mg/kg/dose) with a maximum dose; calculate both the calculated dose and the maximum, and prescribe the lower.
- Verify weight in kilograms at every prescribing encounter; never convert from pounds mentally without a double-check.
- Use oral syringes in milliliters; never teaspoons or tablespoons. Most serious pediatric medication errors are tenfold decimal errors.
- Know common regimens: acetaminophen 10–15 mg/kg/dose every 4–6 hours (maximum 75 mg/kg/day, not to exceed adult maximum); ibuprofen 10 mg/kg/dose every 6–8 hours; amoxicillin 80–90 mg/kg/day for acute otitis media; dexamethasone 0.15–0.6 mg/kg for croup.
- Consider age-specific pharmacokinetics: immature hepatic and renal clearance in neonates, higher weight-based clearance in young children, and variable absorption.
- Stewardship: avoid antibiotics for viral illness, choose the narrowest effective agent, and review allergies and prior cultures.
- Monitor for adverse effects, interactions, and adherence; document the indication.
Worked example
A 12 kg child with acute otitis media needs amoxicillin at 90 mg/kg/day. Reasoning: 12 × 90 = 1080 mg/day, divided twice daily = 540 mg per dose. With 400 mg/5 mL suspension: 540 ÷ 400 × 5 = 6.75 mL twice daily. Check the maximum daily dose and confirm the family has a measuring syringe.
Traps
Using adult doses; exceeding the maximum; prescribing "teaspoons"; failing to adjust for renal or hepatic impairment; ignoring drug interactions; treating viral illnesses with antibiotics.