Pediatric Drug Dosing Guidelines
General Dosing Principles
Pediatric drug dosing should be weight-based for most medications, with body surface area (BSA) normalization reserved for specific drug classes and age groups, while avoiding simple linear scaling from adult doses. 1
Age-Specific Dosing Approaches
Neonates and infants <2 months: Require extreme caution with hepatically metabolized drugs due to immature enzyme systems; doses should be based on therapeutic drug monitoring and clinical response rather than standard weight-based calculations 1
Infants 2-6 months: Weight-based dosing (mg/kg) is appropriate for most medications during this transitional maturation period 1
Children 6 months to 2 years:
Children >2 years: BSA-based dosing becomes the preferred method for most medications, as it more closely follows physiologic parameters 1
Practical Weight-Based Calculation Rule
For rapid clinical dosing estimation: Children ≤30 kg should receive (weight × 2)% of adult dose; children >30 kg should receive (weight + 30)% of adult dose 2. This method follows the BSA curve more accurately than simple mg/kg calculations and reduces major prescribing errors 2.
Organ-Specific Considerations
Hepatically Metabolized Drugs
First 2 months of life: Administer with extreme caution; modify dosing based on therapeutic drug monitoring and clinical response rather than standard formulas 1
After 6 months: Most hepatically cleared drugs can be dosed by BSA, except CYP2D6 and UGT substrates which require weight-based dosing 1
Renally Excreted Drugs
First 2 years: Determine dosing based on markers of renal function (serum creatinine, p-aminohippuric acid clearance) rather than age or weight alone 1
After maturation (>2 years): Normalize doses to BSA for drugs with significant renal excretion 1
Renal impairment in children ≥3 months and >40 kg: Follow adult renal dosing adjustments—GFR 10-30 mL/min requires 12-hour dosing intervals; GFR <10 mL/min requires 24-hour intervals 3
Dose Rounding Strategies
Rounding Categories
Medications should be assigned to specific rounding tolerance categories based on therapeutic index and toxicity risk 4:
Narrow therapeutic index drugs (digoxin, insulin): Round only to nearest 0.1 mL or do not round 4
Dose-dependent toxicity drugs (antibiotics, systemic steroids): Round down to easily administered doses while respecting maximum dose guidelines 4
Standard medications: Can tolerate wider rounding percentages (10-20%) after expert consensus 4
Insufficient pediatric data drugs (mesalamine): Avoid rounding due to unpredictable toxicity 4
Implementation
Expert consensus achieved 10% rounding tolerance for metoclopramide despite tardive dyskinesia risk, reflecting real-world practice patterns 4
Automated dose-rounding systems in e-prescribing can reduce errors when properly calibrated to medication-specific tolerances 4
Common Pitfalls and Error Prevention
High-Risk Error Scenarios
10-fold errors: Occur frequently (8.6% in simulations) even with standardized references, particularly with epinephrine dosing 5
Dilution errors: Incorrect drug dilutions occurred in 33.3% of benzodiazepine administrations in pediatric simulations 5
Air entrainment: Frequently causes under-dosing when drawing from pre-loaded syringes into smaller syringes 5
Weight measurement errors: Led to dosing errors in 12.7% of simulated cases 5
Critical Safety Measures
Verify weight accuracy before any dose calculation, as this is the foundation for all pediatric dosing 5
Double-check dilution calculations independently, especially for high-alert medications 5
Use therapeutic drug monitoring for narrow therapeutic index drugs rather than relying solely on calculated doses 1
Avoid simple linear scaling from adult doses, as developmental pharmacokinetics differ substantially in children 6, 7
Specific Drug Examples
Amoxicillin (Respiratory/ENT Infections)
Children ≥3 months and <40 kg:
Children <3 months: Maximum 30 mg/kg/day divided every 12 hours due to immature renal function 3
Children ≥40 kg: Use adult dosing (500 mg every 12 hours for mild/moderate; 875 mg every 12 hours for severe) 3
Oseltamivir (Influenza Treatment)
- Infants 0-8 months (term): 3 mg/kg/dose twice daily for 5 days 4
- Infants 9-11 months: 3.5 mg/kg/dose twice daily for 5 days 4
- Children ≥12 months: Weight-tiered dosing—≤15 kg: 30 mg twice daily; 15-23 kg: 45 mg twice daily; 23-40 kg: 60 mg twice daily; >40 kg: 75 mg twice daily 4
Epinephrine (Anaphylaxis)
Intramuscular: 0.01 mg/kg (0.01 mL/kg of 1:1000 solution), maximum 0.3 mg per dose; repeat every 5 minutes as needed 4
Intravenous infusion (only for cardiac arrest or profound hypotension after failed IM doses): 0.01 mg/kg (0.1 mL/kg of 1:10,000 solution), maximum 0.3 mg; requires continuous hemodynamic monitoring 4