What is the recommended dose and administration schedule for paracetamol (acetaminophen) infusion in a 16kg child with no known allergies or history of liver disease?

Paracetamol Infusion Dosing for a 16kg Child

For a 16kg child requiring intravenous paracetamol, administer 15 mg/kg per dose (240 mg) every 6 hours, with a maximum daily dose not exceeding 60 mg/kg/day (960 mg/day). 1

Weight-Based Dosing Protocol

• Single dose: 15 mg/kg (240 mg for this 16kg child) 1
• Dosing interval: Every 6 hours 1
• Maximum daily dose: 60 mg/kg/day (960 mg/day for this child) 1
• Maximum number of doses: 4 doses in 24 hours 1

The American Academy of Pediatrics establishes 10-15 mg/kg per dose as the standard range, with 15 mg/kg being appropriate for children in this weight category when adequate analgesia or antipyresis is needed 1. This dosing achieves therapeutic plasma concentrations while maintaining safety margins well below hepatotoxic thresholds 2.

Administration Guidelines

• Infusion time: Administer over 15 minutes for the loading dose if rapid effect is needed, though standard infusion protocols typically use slower administration 2
• Route: Intravenous administration provides consistent absorption compared to rectal formulations, which have erratic absorption patterns 1
• Dilution: Should be diluted in appropriate IV solution per institutional protocols 2

Intravenous acetaminophen has been demonstrated to be well-tolerated in pediatric patients across all age groups, achieving plasma concentrations equivalent to oral administration while avoiding gastrointestinal absorption variability 2.

Safety Considerations and Monitoring

Critical maximum thresholds to prevent hepatotoxicity:

• Never exceed 60 mg/kg in any 24-hour period 1
• Never administer more than 5 doses in 24 hours 1
• Cumulative doses exceeding 90-140 mg/kg/day for multiple consecutive days carry risk of serious hepatic toxicity 3, 4

When to use caution or adjust dosing:

• Children with pre-existing liver disease require dose reduction and specialist consultation 5
• Fasting states or chronic malnutrition may increase toxicity risk through glutathione depletion 4
• Concurrent use of cytochrome P450 2E1-inducing medications warrants closer monitoring 4

Clinical Context for IV Route Selection

Intravenous paracetamol is indicated when:

• Oral intake is contraindicated (active vomiting, NPO status, altered mental status) 1
• Rapid onset of analgesia is required in acute pain settings 2
• Rectal administration is inappropriate or absorption is unreliable 1

The oral syrup formulation provides more rapid and consistent absorption than suppositories when the enteral route is available, but IV administration eliminates absorption variability entirely 1, 2.

Efficacy Expectations

• Onset of action: Clinical improvement in pain or fever typically occurs within 30-60 minutes of IV administration 2
• Duration: Antipyretic and analgesic effects last approximately 4-6 hours, supporting the every-6-hour dosing interval 1
• Therapeutic range: Plasma concentrations achieved with 15 mg/kg dosing fall within the established therapeutic window of 10-20 mcg/mL 2

Common Pitfalls to Avoid

Dosing errors that increase toxicity risk:

• Calculating doses based on outdated age-based rather than weight-based protocols 6
• Failing to account for concurrent paracetamol from other sources (combination products, oral doses given before IV initiation) 4
• Using the 4-hour dosing interval appropriate for oral administration (10 mg/kg) when giving the higher 15 mg/kg IV dose 1

For this specific 16kg child: Give 240 mg IV every 6 hours, maximum 4 doses daily (960 mg total), ensuring no other paracetamol sources contribute to the daily total 1.