Acetaminophen Dosing for a 5-Year-Old Weighing 17.64 kg
For this 5-year-old child weighing 17.64 kg, administer 176–264 mg of oral acetaminophen (10–15 mg/kg) every 4–6 hours, not exceeding 1058 mg per day (60 mg/kg/day) or 5 doses in 24 hours. 1, 2
Weight-Based Calculation
Standard dose range: 10–15 mg/kg per dose 1, 2
- Minimum dose: 17.64 kg × 10 mg/kg = 176 mg
- Maximum dose: 17.64 kg × 15 mg/kg = 264 mg
Practical dosing: Most clinicians use 15 mg/kg for adequate analgesia and antipyresis, which equals 264 mg per dose for this child 3, 4
Dosing Interval and Maximum Daily Limits
Maximum daily dose: 60 mg/kg/day = 1058 mg/day for this 17.64 kg child 1, 2
Maximum number of doses: No more than 5 doses in 24 hours 1, 2
FDA-Labeled Age-Based Dosing Cross-Check
The FDA label recommends for children 4 to under 6 years: 7.5 mL (240 mg) every 4 hours, not to exceed 5 doses in 24 hours 5. This aligns closely with the weight-based calculation of 176–264 mg per dose for this 17.64 kg child.
Route of Administration
Oral syrup is preferred because it provides more rapid and consistent absorption compared to rectal suppositories 1
Rectal administration should be reserved for children who are actively vomiting or in perioperative settings where oral intake is restricted, but absorption is erratic and unpredictable 1
Special Dosing Considerations
Reduce to 10 mg/kg (176 mg) per dose if:
- Malnutrition or fasting >8 hours without adequate caloric intake 1
- Concurrent use of cytochrome P450 inducers (e.g., isoniazid), which increase toxic NAPQI metabolite production 1
- Pre-existing liver disease, though acetaminophen remains safer than NSAIDs in this population 1
Standard 15 mg/kg dosing (264 mg) is appropriate when:
- The child is well-nourished with normal hepatic function 1
- No enzyme-inducing medications are being used 1
Critical Safety Pitfalls to Avoid
Never exceed 60 mg/kg/day (1058 mg/day for this child) to prevent hepatotoxicity 1, 2
Chronic overdosing risk: Exposures greater than 140 mg/kg/day for several days carry serious toxicity risk 3
Weight-based calculations are error-prone in emergencies—pre-calculate doses to minimize errors 2
Avoid combination products that may contain acetaminophen (e.g., cold/flu medications) to prevent inadvertent overdose 3
Practical Prescribing
For this 17.64 kg child:
- Prescribe: Acetaminophen 240–260 mg (rounded from 264 mg for practical measurement) orally every 4–6 hours as needed
- Maximum: 5 doses per 24 hours
- Daily ceiling: Do not exceed 1000 mg in 24 hours
This dosing provides effective analgesia and antipyresis while maintaining a wide safety margin below the hepatotoxic threshold. 1, 2, 3