What is the recommended intravenous (IV) dose of paracetamol (acetaminophen) for a 6-month-old infant weighing 3 kilograms?

IV Paracetamol Dosing for a 6-Month-Old Infant Weighing 3 kg

For a 6-month-old infant weighing 3 kg, the recommended IV paracetamol dose is 7.5 mg (2.5 mg/kg) every 6 hours, with a maximum daily dose of 30 mg/kg/day.

Dosing Rationale

The appropriate dosing for IV paracetamol in infants requires careful consideration of the child's weight, age, and clinical condition. For this underweight infant (3 kg at 6 months), dosing must be adjusted accordingly:

Weight-Based Dosing Calculation

• Standard IV paracetamol dosing for infants: 10-15 mg/kg/dose
• For an underweight infant: Lower end of dosing range (7.5-10 mg/kg/day) is preferred
• For this 3 kg infant: 7.5 mg (2.5 mg/kg) per dose is appropriate
• Frequency: Every 6 hours (maximum 4 doses per day)
• Maximum daily dose: 30 mg/kg/day (90 mg total daily for this infant)

Administration Guidelines

1. Preparation and Administration

   • Dilute in appropriate volume of compatible IV fluid
   • Administer over 15 minutes to minimize risk of hypotension
   • Use infusion pump for accurate delivery
   • Monitor vital signs during and after administration

2. Clinical Monitoring

   • Assess pain scores before and after administration
   • Monitor for signs of hepatotoxicity (especially with repeated dosing)
   • Check for signs of hemodynamic instability during administration

Special Considerations

Cautions for This Patient

• This infant is significantly underweight for age (expected weight at 6 months: 7-8 kg)
• Lower dosing is warranted due to:
  • Reduced body weight
  • Potentially immature hepatic metabolism
  • Risk of accumulation with repeated dosing

Safety Monitoring

• Monitor liver function if treatment extends beyond 48-72 hours
• Ensure accurate documentation of all doses to prevent medication errors
• Calculate maximum daily dose based on actual weight (not ideal weight)

Alternative Approaches

If IV paracetamol is ineffective or contraindicated:

• Consider non-pharmacological pain management strategies
• Assess need for opioid analgesia if pain is severe
• Consider oral paracetamol if IV route no longer necessary

Common Pitfalls to Avoid

1. Dosing Errors: Never exceed 15 mg/kg/dose or 60 mg/kg/day in infants
2. Calculation Mistakes: Always double-check weight-based calculations
3. Inadequate Monitoring: Ensure proper pain assessment and vital sign monitoring
4. Prolonged Use: Limit duration of IV paracetamol when possible to reduce risk of hepatotoxicity
5. Concomitant Medications: Be cautious with other hepatotoxic medications

The reduced dosing for this underweight infant balances the need for pain control while minimizing risks of adverse effects, particularly given the vulnerability of a 3 kg infant at 6 months of age.