Acetaminophen Dosing for a 35-lb Child
For a 35-lb (approximately 16-kg) child, administer 240 mg of liquid acetaminophen (paracetamol) every 4-6 hours as needed, not exceeding 5 doses in 24 hours.
Weight-Based Dosing Calculation
- The standard pediatric dose of acetaminophen is 15 mg/kg per dose, which provides adequate antipyretic and analgesic effect 1, 2.
- For a 16-kg child: 15 mg/kg × 16 kg = 240 mg per dose 2.
- This dose should be administered every 4-6 hours as needed 1.
- The maximum daily dose should not exceed 60-75 mg/kg/day (approximately 960-1,200 mg/day for this child) 1, 3.
Dosing Interval and Frequency
- Doses can be given every 4 hours if needed for persistent fever or pain, up to a maximum of 4-5 doses per 24-hour period 1, 3.
- The 10 mg/kg dose is insufficient and does not consistently achieve therapeutic plasma concentrations (10-20 μg/mL) needed for antipyresis 4.
- A 15 mg/kg dose is more effective than 10 mg/kg and maintains temperature reduction for approximately 6 hours 3.
Liquid Formulation Considerations
- Most pediatric acetaminophen suspensions are available as 160 mg/5 mL concentration.
- For 240 mg: administer 7.5 mL of the 160 mg/5 mL suspension 2.
- Always verify the concentration on the product label, as formulations vary 4.
Critical Safety Points
- Never exceed 75 mg/kg/day total daily dose, as chronic overdosing (>140 mg/kg/day for several days) carries risk of serious hepatotoxicity 1.
- Single ingestions of more than ten times the recommended dose are potentially toxic 1.
- Weight-based dosing is superior to age-based dosing and prevents underdosing errors that occur in up to 30% of cases with age-based recommendations 4.
Common Pitfalls to Avoid
- Do not use age-based dosing charts that recommend fixed doses (such as 160 mg for "ages 2-3"), as these frequently result in inadequate dosing for heavier children in the weight range 4.
- Avoid the 10 mg/kg dose, which consistently fails to achieve therapeutic plasma concentrations 3, 4.
- Do not combine multiple acetaminophen-containing products (e.g., cold medications) without accounting for total daily acetaminophen intake 1.