What is the recommended dosage of paracetamol (acetaminophen) for infants?

Paracetamol (Acetaminophen) Dosing for Infants

For infants aged 2 months to under 2 years, administer paracetamol at 10-15 mg/kg per dose every 4-6 hours, not exceeding 60-90 mg/kg/day, with infants under 2 months requiring physician consultation before use. 1

Standard Dosing by Age

Infants Under 2 Months

• Consult a physician before administering paracetamol 1
• No standardized dosing guidelines exist for neonates under 1 month of age 2
• For neonates when prescribed by a physician: 30 mg/kg/day achieves effective therapeutic concentrations, though pharmacokinetic data suggests higher doses may be appropriate 2

Infants 2 Months to Under 2 Years

• Dose: 10-15 mg/kg per dose 3, 4
• Frequency: Every 4-6 hours 1, 5
• Maximum daily dose: 60-90 mg/kg/day 5, 2
• Do not exceed 5 doses in 24 hours 1

Specific Age-Based Dosing from FDA Label

• 2 to under 4 years: 5 mL (160 mg) every 4 hours, not exceeding 5 doses in 24 hours 1
• This translates to approximately 10-15 mg/kg for typical weight ranges in this age group 1

Critical Dosing Considerations

Optimal Therapeutic Dose

• 15 mg/kg is significantly more effective than lower doses (≤10 mg/kg) for both fever and pain management 4
• Older studies using subtherapeutic doses of ≤10 mg/kg showed paracetamol to be less effective than NSAIDs, but 15 mg/kg demonstrates equivalent efficacy 4
• The 15 mg/kg dose has a tolerability profile similar to placebo and NSAIDs when used short-term 4

Age-Specific Adjustments

• Infants 1-3 months: 60-65 mg/kg/day is suggested in literature, though pharmacokinetic data favors higher doses 2
• Infants have prolonged elimination half-lives (55-90 hours vs. 30 hours in adults), requiring careful weight-based dosing rather than extrapolating adult doses 6

Safety Thresholds and Toxicity Prevention

Maximum Safe Doses

• Single doses exceeding 10 times the recommended dose (>150 mg/kg) are potentially hepatotoxic 5
• Chronic exposure >140 mg/kg/day for several consecutive days carries risk of serious liver toxicity 5
• Daily doses should not exceed 90-95 mg/kg/day to prevent cumulative hepatic and renal damage 2

Common Prescribing Errors

• In one audit, 17% of prescriptions exceeded 95 mg/kg/day, though only 3% of children actually received these excessive doses due to pharmacy and nursing oversight 2
• Carefully record all dose times when using paracetamol to avoid accidentally exceeding maximum recommended doses 7

Administration Guidelines

Formulation and Delivery

• For infants unable to swallow, paracetamol can be administered as an oral suspension 1
• The FDA-approved oral solution provides 160 mg per 5 mL for the 2-4 year age range 1

Dosing Interval

• Maintain 4-6 hour intervals between doses 1, 5
• The UK recommends 10 mg/kg every 4 hours up to maximum of 4 doses per day 5
• Australia recommends 15 mg/kg every 4 hours up to total of 60 mg/kg/day 5

Clinical Pitfalls to Avoid

• Never use paracetamol in infants under 2 months without physician consultation 1
• Avoid using subtherapeutic doses (<10 mg/kg), as these show inferior efficacy compared to appropriate dosing 4
• Do not exceed 5 doses in 24 hours for children under 12 years 1
• When fever persists, consider that it is a relatively short-lived symptom that may resolve within 48 hours to 5 days regardless of treatment 7
• Paracetamol shows lower risk of adverse events compared to NSAIDs when used at repetitive doses for consecutive days 4