Yes, 650 mg of paracetamol is safe and appropriate for a 10-year-old boy weighing 49 kg.
For a 10-year-old child weighing 49 kg (>40 kg), the recommended single dose of paracetamol is 650 mg (or up to 15 mg/kg), which can be given every 4-6 hours, not exceeding 5-6 doses in 24 hours. 1, 2
Dosing Rationale
The child's weight of 49 kg places him in the adult dosing category according to multiple pediatric guidelines:
- Weight-based dosing: Children weighing >40 kg should receive adult doses 3, 4
- Standard single dose: 10-15 mg/kg per dose 1, 5, 6
- For 49 kg: This equals 490-735 mg per dose, making 650 mg well within the safe and effective range
- FDA-approved dosing: Children ≥12 years receive 650 mg every 4-6 hours 2
Maximum Daily Limits
The critical safety consideration is the maximum daily dose of 60-90 mg/kg/day 1, 7, 8:
- For 49 kg: Maximum daily dose = 2,940-4,410 mg
- Six doses of 650 mg = 3,900 mg/day (well within safe limits)
- Never exceed 4 grams (4,000 mg) per day in children 2
Dosing Schedule
Give 650 mg every 4-6 hours as needed, with a maximum of 5-6 doses in 24 hours 1, 2, 6. The 4-hour minimum interval is important to prevent accumulation and maintain therapeutic levels while avoiding toxicity.
Important Caveats
- Avoid repeated supratherapeutic dosing: Do not exceed recommended daily limits for consecutive days, as this can cause severe hepatotoxicity even without acute overdose 9, 10, 11
- Risk factors for toxicity: Reduce dosing to 100 mg/kg/day maximum if the child has prolonged fasting, malnutrition, chronic illness, or concurrent use of certain medications 12, 11
- Accurate dosing is critical: Caregivers frequently make dosing errors by giving medication too frequently (e.g., every 2 hours instead of every 4-6 hours), which can lead to unintentional overdose 9
Clinical Effectiveness
The 10-15 mg/kg dose (650 mg for this child) provides:
- Rapid onset of fever reduction within 1 hour 6
- Maximum temperature reduction at approximately 3 hours post-administration 6
- Efficacy equivalent to NSAIDs when dosed appropriately 5, 6
Bottom line: 650 mg is the correct dose for this child, given every 4-6 hours as needed, not exceeding 6 doses daily.