Acetaminophen (Tylenol) Dosing for Children
Administer acetaminophen at 10–15 mg/kg per dose every 4–6 hours, with a maximum daily dose of 60 mg/kg per day (not to exceed 5 doses in 24 hours). 1
Weight-Based Dosing
- Standard dose: 10–15 mg/kg per dose 1
- Dosing interval: Every 4–6 hours 1
- Maximum daily dose: 60 mg/kg per day 1
- Maximum number of doses: Do not exceed 5 doses in 24 hours 1
The 10 mg/kg dose often fails to achieve therapeutic plasma concentrations (10–20 μg/mL) needed for effective antipyresis, while 15 mg/kg consistently reaches therapeutic levels. 2 For optimal fever reduction and pain control, use 15 mg/kg per dose rather than 10 mg/kg. 2, 3
Age-Specific Considerations
- Infants under 3 months: Acetaminophen is the only recommended analgesic; use 15 mg/kg if weight is less than 10 kg 1
- Children weighing more than 40 kg: Use adult dosing 1, 4
Route of Administration
- Oral suspension (preferred): Absorbed more rapidly and provides more consistent response compared to rectal suppositories 1
- Rectal suppositories: Use cautiously due to erratic absorption; some children may receive inadequate analgesia while others risk accumulation with repeated dosing 1
- Intravenous: For neonates (full-term to 28 days), use either 12.5 mg/kg every 6 hours or 15 mg/kg every 8 hours; for infants and children, use either 12.5 mg/kg every 4 hours or 15 mg/kg every 6 hours 5
Reduced Dosing for High-Risk Populations
Use 10 mg/kg (lower end of range) in children with:
- Chronic malnutrition or fasting >8 hours without adequate caloric intake 1
- Medications that induce cytochrome P450 enzymes (e.g., isoniazid) 1
- Pre-existing liver disease 1
These conditions increase hepatotoxicity risk by raising production of the toxic NAPQI metabolite or reducing hepatic reserve. 1
Alternating with Ibuprofen
- Acetaminophen: Every 4–6 hours 1
- Ibuprofen: Every 6–8 hours (not recommended for infants under 6 months) 1
- Stagger timing: Administer medications every 3–4 hours if both are needed 1
Special Clinical Situations
- Post-vaccination fever: Can be given at time of vaccination and every 4 hours for 24 hours 1
- History of febrile seizures: Acetaminophen at 15 mg/kg can be given prophylactically to reduce fever risk, though it does not prevent febrile seizures 1
- Vomiting children: Consider rectal administration when oral intake is not tolerated 1
Common Pitfalls to Avoid
Age-based dosing errors: Up to 30% of febrile children receive inadequate acetaminophen dosages at home due to age-based rather than weight-based dosing. 2 Always calculate dose based on current weight, not age.
Manufacturer dosing inadequacy: The standard 160 mg dose recommended by some manufacturers is effective only for children weighing exactly 10.9 kg; it underdoses heavier children and overdoses lighter ones. 2 Always use weight-based calculation.
Underdosing with 10 mg/kg: This dose frequently fails to achieve therapeutic plasma concentrations. 2, 3 Use 15 mg/kg for reliable antipyretic and analgesic effect.