Pediatric Acetaminophen Dosing Conversion
Use 10-15 mg/kg per dose every 4-6 hours for pediatric acetaminophen dosing, with a maximum of 60 mg/kg per day or 5 doses in 24 hours—do not simply scale down adult tablets. 1
Weight-Based Dosing Algorithm
The standard pediatric dose is 10-15 mg/kg per dose, administered every 4-6 hours. 1 This is the most reliable method for converting from adult to pediatric dosing:
- Calculate the child's weight in kilograms 1
- Multiply weight by 10-15 mg to determine the appropriate single dose 1, 2
- Administer every 4-6 hours as needed 1
- Never exceed 60 mg/kg per day or 5 doses in 24 hours 1
Why Adult Tablets Cannot Be Simply Divided
Adult acetaminophen formulations (typically 325-500 mg tablets) are not designed for pediatric use. 3 The FDA labeling for adult acetaminophen products explicitly states "children under 12 years - do not use" for certain formulations. 3 Weight-based calculation is essential because:
- A 10 kg child requires 100-150 mg per dose 1
- A 20 kg child requires 200-300 mg per dose 1
- These doses cannot be accurately achieved by dividing adult tablets 4
Special Considerations by Age
Infants under 3 months: Use 15 mg/kg if weight is less than 10 kg—acetaminophen is the only recommended analgesic in this age group. 1
Infants 3 months to 6 months: Continue with 10-15 mg/kg dosing every 4-6 hours. 1
Children over 40 kg: May receive adult dosing schedules. 1
Formulation Selection
Oral syrup is preferred over suppositories because it provides more rapid absorption and consistent response. 1 Rectal acetaminophen has erratic absorption and should be reserved for children who are actively vomiting or in perioperative situations where oral intake is restricted. 1
Common Dosing Errors to Avoid
Studies demonstrate that up to 30% of children receive inadequate acetaminophen doses at home, primarily due to age-based rather than weight-based dosing. 4 Specific pitfalls include:
- Underdosing: 27% of children receive less than 10 mg/kg, which may not achieve therapeutic plasma concentrations (10-20 μg/mL needed for antipyresis). 5, 4
- Overdosing: 12% receive 20 mg/kg or more per dose, risking toxicity. 5
- Excessive frequency: Some parents administer doses every 2-3 hours instead of the recommended 4-6 hour interval. 5
Maximum Daily Limits
The absolute maximum is 60 mg/kg per day or 5 doses in 24 hours, whichever is lower. 1 This safety threshold prevents hepatotoxicity and must never be exceeded regardless of fever persistence or pain severity.