What is the appropriate ibuprofen dosage for a 9‑month‑old infant weighing approximately 7–10 kg?

Ibuprofen Dosing for a 9-Month-Old Infant

For a 9-month-old infant weighing 7–10 kg, administer ibuprofen at 5–10 mg/kg per dose every 6–8 hours as needed, with a maximum daily dose of 30–40 mg/kg/day. 1

Weight-Based Dosing Algorithm

• For infants 3–12 months old weighing >5–6 kg, use 5–10 mg/kg per dose 1
• Dosing frequency: Every 6–8 hours (3–4 times daily maximum) 1
• Maximum total daily dose: 30–40 mg/kg/day 1

Practical Calculation for Your Patient

• 7 kg infant: 35–70 mg per dose (every 6–8 hours)
• 8 kg infant: 40–80 mg per dose (every 6–8 hours)
• 9 kg infant: 45–90 mg per dose (every 6–8 hours)
• 10 kg infant: 50–100 mg per dose (every 6–8 hours)

Critical Safety Contraindications

Do NOT administer ibuprofen if the infant has:

• Diarrhea and/or vomiting (with or without fever), as dehydration significantly increases the risk of acute renal failure 2, 3
• Signs of volume depletion or hypovolemia, even moderate dehydration is dangerous 3
• Active varicella (chickenpox) due to increased risk of invasive group A streptococcal infection 2, 4
• Wheezing or persistent asthma 2
• Body weight <5–6 kg 1

Route of Administration

• Oral route is strongly preferred over rectal administration 1
• Rectal ibuprofen shows erratic and unreliable absorption, especially in young infants 1

Clinical Context and Appropriate Use

Ibuprofen should be reserved for inflammatory pain, NOT routine fever management 2

• The drug is most appropriate for inflammatory pain conditions in this age group 2
• Avoid using ibuprofen as a routine antipyretic except in rare circumstances 2
• Most adverse events reported in the literature occurred when ibuprofen was used for fever or flu-like symptoms 2

Hydration Monitoring

Before and during ibuprofen administration:

• Ensure the infant is adequately hydrated 1, 3
• Seven cases of acute renal failure were documented in children who received therapeutic ibuprofen doses (11.5–32 mg/kg/day) for only 1–3 days while experiencing diarrhea/vomiting 3
• Renal failure developed with creatinine levels reaching 180–650 μmol/L, with one patient requiring emergency dialysis 3
• Complete recovery occurred within 3–9 days after stopping ibuprofen and rehydrating 3

Common Pitfalls to Avoid

• Never dose by age alone—always use weight-based calculations 1
• Do not exceed 40 mg/kg/day total regardless of symptom severity 1
• Do not use in any infant with gastrointestinal illness (diarrhea/vomiting), as even moderate volume depletion creates dangerous conditions for NSAID-induced acute renal failure 3
• Avoid rectal formulations due to unpredictable absorption in this age group 1

Duration of Therapy

• Short-term use (≤3 days) is considered safe when the above precautions are followed 1
• The safety profile at OTC doses (which align with pediatric weight-based dosing) shows low risk for serious gastrointestinal, renal, and cardiovascular events when used appropriately 5