Paracetamol Dosing for Underweight 12-Year-Old Children
For a 12-year-old underweight child, paracetamol should be dosed based on actual body weight at 10-15 mg/kg per dose (not age-based dosing), given every 4-6 hours, with a maximum of 4 doses per day and not exceeding 60-75 mg/kg/day total. 1, 2
Weight-Based Dosing is Essential for Underweight Children
- Age-based dosing guidelines systematically underdose underweight children and overdose overweight children, making weight-based calculation critical for safe and effective therapy 3
- For children at the 9th percentile for weight (underweight), age-based dosing can result in doses above therapeutic limits, while children at the 91st percentile receive subtherapeutic doses 3
- The recommended single dose range is 10-15 mg/kg, administered every 4-6 hours 1, 2
Specific Dosing Parameters
- Single dose: 10-15 mg/kg per dose 1, 2
- Dosing interval: Every 4-6 hours 1, 2
- Maximum frequency: 4 doses per 24 hours 2
- Maximum daily dose: 60-75 mg/kg/day 2, 4
For example, if the 12-year-old weighs 30 kg (significantly underweight for age):
- Single dose would be 300-450 mg per dose
- Maximum daily dose would be 1800-2250 mg/day
Critical Safety Considerations
- Chronic overdosing risk: Exposures greater than 140 mg/kg/day for several days carry risk of serious hepatotoxicity and liver failure 2
- Parents must carefully record all dose times to avoid accidentally exceeding maximum recommended doses, as 8-11% of parents in clinical studies exceeded recommended dosing frequency 4
- Single ingestions of more than 10 times the recommended dose are potentially hepatotoxic 2
Clinical Context
- Paracetamol has equivalent efficacy to other analgesic-antipyretics and is remarkably well-tolerated when used in recommended doses 1, 2
- It remains the first-choice over-the-counter treatment for analgesia and antipyresis in children 2
- Fever typically resolves within 24-48 hours, and parents should be counseled that fever is relatively short-lived 4