Acetaminophen Pediatric Dosing
Administer acetaminophen at 10-15 mg/kg per dose every 4-6 hours in children, with a maximum of 5 doses per day (not exceeding 75 mg/kg/day or 4000 mg/day total). Weight-based dosing is superior to age-based dosing and should always be used when the child's weight is known 1, 2.
Standard Dosing Protocol
Single Dose Recommendations:
- Standard dose range: 10-15 mg/kg per dose 1, 3
- Dosing interval: Every 4-6 hours as needed 1, 3
- Maximum frequency: Up to 5 doses per 24-hour period 4
- Maximum daily dose: 75 mg/kg/day (not to exceed 4000 mg/day in adolescents) 1, 3
Loading Dose Strategy
For acute fever management, a loading dose approach may be more effective:
This regimen achieves therapeutic plasma concentrations (10-20 μg/mL) more rapidly and maintains them more consistently 3.
Critical Dosing Considerations
The 10 mg/kg dose is often inadequate:
- Pharmacokinetic modeling demonstrates that 10 mg/kg produces peak plasma concentrations of only 6.38-8.55 μg/mL, which falls below the therapeutic range of 10-20 μg/mL needed for antipyresis 2
- A 15 mg/kg dose achieves plasma concentrations of 9.57-12.8 μg/mL, which is more likely to reach therapeutic levels 2
- For moderate fever, start with 15 mg/kg rather than 10 mg/kg to ensure adequate antipyretic effect 2
Common dosing errors to avoid:
- Age-based dosing leads to significant under- or overdosing in up to 39% of children 2
- Manufacturer's fixed-dose recommendations (e.g., 160 mg for ages 2-3 years) are only appropriate for children at the lower end of the weight range and result in underdosing for heavier children in that age bracket 2
- Parents frequently administer incorrect doses: 27% give less than 10 mg/kg (underdosing) and 12% give more than 20 mg/kg (overdosing) 4
Route-Specific Guidance
Oral suspension vs. suppositories:
- Oral suspension provides more consistent absorption and predictable response compared to rectal suppositories 3
- Both routes require 10-15 mg/kg dosing, but oral is preferred when feasible 3
Practical Implementation
Weight-based dosing table approach:
- Create dosing schedules based on actual weight rather than age 1
- Ensure each dose falls within the 10-15 mg/kg range 1
- Educate parents on proper measurement techniques and dosing intervals 4
Safety Parameters
Therapeutic plasma concentration: 10-20 μg/mL for antipyretic effect 3 Half-life: 1-3.5 hours in children 3 Time to maintain fever reduction: At least 10 mg/kg is required to keep temperature 1.5°C below baseline for 6 hours 3
Key Clinical Pitfall
The most common error is underdosing. Many parents and even some dosing guides recommend insufficient amounts of acetaminophen 1, 4. When prescribing, explicitly state the weight-based dose (e.g., "Give 15 mg/kg, which equals X mg for your child") rather than relying on age-based recommendations or manufacturer's packaging instructions 2.