What is the appropriate Flexon (ibuprofen/paracetamol) tablet dose and dosing interval for a 30‑kg child?

Flexon Dosing for a 30-kg Child

For a 30-kg child, administer paracetamol 300–450 mg per dose (typically one tablet if Flexon contains 325–500 mg paracetamol) every 4–6 hours, and ibuprofen 300 mg per dose (typically one tablet if Flexon contains 400 mg ibuprofen) every 6–8 hours, ensuring you do not exceed 5 doses of paracetamol or 3 doses of ibuprofen in 24 hours. 1

Weight-Based Dose Calculation

Paracetamol Component

• The standard paracetamol dose is 10–15 mg/kg per dose every 4–6 hours. 1
• For a 30-kg child, this equals 300–450 mg per dose. 1, 2
• The maximum daily dose is 60 mg/kg/day (1,800 mg/day for this child) or no more than 5 doses in 24 hours. 1

Ibuprofen Component

• The standard ibuprofen dose is 10 mg/kg per dose every 6–8 hours. 1
• For a 30-kg child, this equals 300 mg per dose. 1, 3
• Administer no more than 3 doses in 24 hours. 1

Practical Tablet Dosing

• If Flexon tablets contain 325 mg paracetamol + 400 mg ibuprofen (a common formulation):

  • Give one tablet per dose, which provides paracetamol 325 mg (within the 300–450 mg range) and ibuprofen 400 mg (slightly above the calculated 300 mg but within safe limits). 1

• Dosing interval: Alternate the medications so paracetamol is given every 4–6 hours and ibuprofen every 6–8 hours, staggering them approximately 3–4 hours apart if both are needed. 1

Critical Safety Considerations

Avoiding Overdose

• Never exceed 60 mg/kg/day of paracetamol (1,800 mg/day for 30 kg) or give more than 5 doses in 24 hours, as hepatotoxicity risk increases significantly above this threshold. 1, 2
• Carefully track all dose times to prevent inadvertently exceeding maximum recommended doses, especially when using combination products. 4
• Parents frequently exceed the recommended maximum number of doses (8% for paracetamol, 11% for ibuprofen in one trial), so explicit written instructions are essential. 4

Special Populations Requiring Dose Reduction

• Reduce paracetamol to 10 mg/kg per dose (300 mg for this child) if the child:
  • Has fasted for more than 8 hours without adequate caloric intake 1
  • Is chronically malnourished 1
  • Is taking cytochrome P450-inducing medications (e.g., isoniazid) 1
  • Has pre-existing liver disease 1

When to Use Ibuprofen Cautiously

• Ibuprofen is generally not recommended for infants under 6 months. 1
• For children with stable neurologic conditions or pain management needs, paracetamol is generally safer than NSAIDs. 1

Clinical Effectiveness

• Combination therapy (paracetamol + ibuprofen) provides an additional 2.5–4.4 hours without fever over 24 hours compared to either agent alone. 4
• In the first 4 hours, combination therapy provides 55 minutes more fever-free time than paracetamol alone and may be as effective as ibuprofen alone. 4
• Ibuprofen 10 mg/kg and paracetamol 15 mg/kg have equivalent efficacy and tolerability when used separately. 3

Common Pitfalls to Avoid

• Do not assume fever requires aggressive treatment: Fever itself is relatively short-lived and does not require treatment unless associated with discomfort. 4
• Do not use paracetamol to prevent febrile seizures: It improves comfort but does not prevent seizure recurrence. 1
• Avoid using both medications routinely: Reserve combination therapy for situations where monotherapy provides inadequate symptom control, weighing the extra 2.5 hours without fever against the risk of dosing errors. 4