Acetaminophen Dosing for an 8.6-kg Child
Give 4 mL of standard pediatric acetaminophen suspension (160 mg per 5 mL).
Dose Calculation
For this 8.6-kg child, the recommended dose is 10–15 mg/kg, which equals 86–129 mg per dose. 1
- Using the standard 15 mg/kg dose: 8.6 kg × 15 mg/kg = 129 mg 1
- Using the standard suspension concentration of 160 mg per 5 mL, the volume needed is: (129 mg ÷ 160 mg) × 5 mL = 4.0 mL 1
- This dose can be repeated every 4–6 hours as needed, not to exceed 5 doses in 24 hours 1
Dosing Rationale
The 15 mg/kg dose is preferred over 10 mg/kg because pharmacokinetic modeling demonstrates that 10 mg/kg fails to achieve therapeutic plasma concentrations (10–20 μg/mL) needed for effective antipyresis. 2
- Clinical studies confirm that 15 mg/kg provides superior antipyretic efficacy compared to 10 mg/kg, with maximum temperature reduction occurring approximately 3 hours after administration 3
- The 15 mg/kg dose maintains temperature reduction of at least 1.5°C below baseline for 6 hours 4
- Oral suspension formulations are absorbed more rapidly and provide more consistent responses compared to rectal suppositories 1
Safety Considerations
The maximum daily dose must not exceed 60 mg/kg per day or 5 doses in 24 hours. 1
- For this 8.6-kg child, the maximum daily dose is 516 mg (8.6 kg × 60 mg/kg) 1
- At 129 mg per dose, this allows for 4 doses safely within 24 hours with a margin of safety 1
- Common pitfall: Age-based dosing leads to underdosing in up to 30% of children; weight-based dosing is essential for accuracy 2
Special Circumstances Requiring Dose Reduction
Reduce the dose to 10 mg/kg (86 mg = 2.7 mL) if the child has any of the following conditions: 1