Paracetamol IV Dosing for a 6-Year-Old Child (21 kg)
For this 6-year-old child weighing 21 kg with fever, administer 315 mg (2.1 mL) of intravenous paracetamol every 6 hours, NOT every 4 hours.
Correct Dosing Calculation
The appropriate dose is 15 mg/kg every 6 hours for children aged 2-12 years 1:
- Dose per administration: 15 mg/kg × 21 kg = 315 mg
- Volume to administer: 315 mg ÷ 150 mg/mL = 2.1 mL
- Dosing interval: Every 6 hours (not every 4 hours)
- Maximum daily dose: 75 mg/kg/day = 1,575 mg/day (or four doses of 315 mg) 1
Critical Dosing Error to Avoid
Your proposed "every 4 hours" schedule is incorrect and potentially dangerous. The FDA-approved dosing for children 2-12 years specifies either:
- 15 mg/kg every 6 hours, OR
- 12.5 mg/kg every 4 hours 1
If you were to dose every 4 hours, you must reduce the dose to 12.5 mg/kg (262.5 mg or 1.75 mL), not 15 mg/kg 1. Using 15 mg/kg every 4 hours would exceed the maximum daily dose of 75 mg/kg and risk hepatotoxicity 1.
Administration Guidelines
- Infusion time: Administer as a 15-minute intravenous infusion 1
- Minimum dosing interval: 4 hours between doses (if using the 12.5 mg/kg regimen) or 6 hours (if using the 15 mg/kg regimen) 1
- Do not exceed: 75 mg/kg per day or 4,000 mg per day (whichever is less) 1
Supporting Evidence
The pharmacokinetic studies demonstrate that 15 mg/kg every 6 hours achieves therapeutic plasma concentrations (target mean steady-state concentration of 9-11 mg/L) for fever reduction and analgesia in children 2, 3. Research comparing dosing regimens confirms that the antipyretic effect depends on total dose over a given time interval, and the standard 10-15 mg/kg dose is safe and effective when administered appropriately 4.
The 15 mg/kg every 6 hours regimen maintains consistent therapeutic effect while staying within safe dosing limits 4. Dosing more frequently than recommended increases the risk of hepatotoxicity, which is the most serious adverse effect of acetaminophen overdose 1.