Ibuprofen Dosing Volume in Children
For pediatric patients, administer ibuprofen at 10 mg/kg per dose every 6-8 hours using the commercially available oral suspension (typically 100 mg/5 mL concentration), which translates to 0.5 mL per kg of body weight per dose when using standard formulations. 1
Calculating the Volume to Administer
The volume in mL depends on three factors:
- Child's weight in kg
- Concentration of the ibuprofen suspension (most commonly 100 mg/5 mL in the US)
- Dose per kg (10 mg/kg is the standard recommended dose)
Standard Calculation Formula:
Volume (mL) = [Weight (kg) × 10 mg/kg] ÷ [Concentration in mg/mL]
For the most common 100 mg/5 mL suspension (= 20 mg/mL):
- Volume (mL) = Weight (kg) × 0.5 mL/kg 1
Practical Examples:
- 10 kg child: 5 mL per dose 1
- 15 kg child: 7.5 mL per dose 1
- 20 kg child: 10 mL per dose 1
- 30 kg child: 15 mL per dose (but verify not exceeding tablet-equivalent dosing) 2
Route-Specific Considerations
Oral Administration (Preferred Route):
- Dose: 10 mg/kg every 6-8 hours 1
- Maximum daily dose: 30-40 mg/kg/day 3
- Can be administered with meals to improve gastrointestinal tolerability 2
Rectal Administration (Less Reliable):
- Dose: 10 mg/kg every 8 hours 1
- Important caveat: Rectal absorption is erratic and less reliable, especially in young infants, making this route less preferred 3
Intravenous Administration:
- Dose: 10 mg/kg every 6 hours (up to 4 doses/day) 1
- Approved for children ≥6 months, though recent data support safety in infants 1-6 months 4
Age-Specific Guidance
Infants 3-6 Months:
- Use 5-10 mg/kg per dose, 3-4 times daily 3
- Requires body weight >5-6 kg 3
- Critical: Ensure adequate hydration 3
- Short-term use only 3
Children ≥6 Months:
- Standard dose: 10 mg/kg every 6-8 hours 1
- Maximum single dose typically does not exceed 400 mg in controlled trials 2
- Maximum daily dose: 40 mg/kg (not to exceed 2400 mg/day in chronic use, 3200 mg/day maximum in adults) 2
Common Pitfalls to Avoid
Concentration confusion: Always verify the concentration of your specific ibuprofen formulation before calculating volume. The FDA-approved oral suspension is 100 mg/5 mL (20 mg/mL), but compounded formulations may differ 2. Some international formulations use different concentrations.
Underdosing: Doses of 2.5-5 mg/kg are less effective than 10 mg/kg for fever reduction, particularly after the initial dose 5. The effective dose range is 7.5-10 mg/kg 6.
Frequency errors: The dosing interval is every 6-8 hours (not every 4 hours as with some other analgesics) 1, 3. Maximum of 4 doses per 24 hours 1.
Dehydration risk: Particularly important in infants 3-6 months—ensure adequate hydration before and during ibuprofen therapy 3.
Rectal route overreliance: Avoid assuming rectal administration provides equivalent bioavailability to oral; absorption is erratic, especially in young infants 3.