What is the appropriate dose of amoxicillin/clavulanate potassium oral suspension (250 mg amoxicillin/5 mL, 62.5 mg clavulanate/5 mL) for a 4‑month‑old infant weighing 8.7 kg with serous otitis media?

Dosing Amoxicillin/Clavulanate for Serous Otitis Media in a 4-Month-Old

Serous otitis media (otitis media with effusion) does not require antibiotic therapy, and amoxicillin/clavulanate should not be prescribed for this condition. 1

Critical Distinction: Serous vs. Acute Otitis Media

• Serous otitis media (also called otitis media with effusion) is characterized by middle ear fluid without signs of acute infection—no bulging tympanic membrane, no acute ear pain, and no fever. 1
• This condition is viral or non-infectious in the vast majority of cases and resolves spontaneously without antibiotics. 1
• Antibiotics provide no benefit for serous otitis media and expose the infant to unnecessary adverse effects (diarrhea occurs in 25% with high-dose amoxicillin/clavulanate) and promote antimicrobial resistance. 1

When Antibiotics ARE Indicated: Acute Otitis Media

If this infant actually has acute otitis media (AOM)—defined by acute ear pain, bulging tympanic membrane, and middle ear effusion—then antibiotic therapy is appropriate for a 4-month-old. 1

High-Dose Regimen for Infants < 2 Years

• Infants under 2 years with AOM require high-dose amoxicillin/clavulanate: 90 mg/kg/day of amoxicillin with 6.4 mg/kg/day of clavulanate, divided into 2 doses every 12 hours. 1
• For an 8.7 kg infant: 90 mg/kg/day × 8.7 kg = 783 mg amoxicillin per day, given as 391.5 mg (approximately 390 mg) twice daily. 1

Practical Dosing with the 250 mg/5 mL Formulation

• The suspension you have (250 mg amoxicillin per 5 mL) provides 50 mg amoxicillin per mL. 2
• To deliver 390 mg per dose: 390 mg ÷ 50 mg/mL = 7.8 mL twice daily (every 12 hours). 1
• Round to 8 mL twice daily for practical administration. 1
• This provides approximately 800 mg amoxicillin per day (92 mg/kg/day), which is within the recommended 90 mg/kg/day range. 1

Age Restriction: Verify This Formulation Is Appropriate

• Amoxicillin/clavulanate is approved for infants ≥ 3 months of age for bacterial infections including AOM. 1
• A 4-month-old infant meets this age criterion. 1
• For infants < 3 months, intravenous ampicillin plus gentamicin or cefotaxime is preferred over oral amoxicillin/clavulanate, and specialist consultation is required. 1

Treatment Duration and Monitoring

• Continue treatment for 10 days for infants under 2 years with AOM. 1
• Clinical improvement (reduced fever, less irritability, improved feeding) should occur within 48–72 hours. 1
• If no improvement or worsening after 48–72 hours, reassess the diagnosis and consider switching to intramuscular ceftriaxone or further evaluation for complications. 1

Common Pitfall to Avoid

• Do not prescribe antibiotics for isolated tympanic membrane redness without bulging or effusion—this does not meet criteria for bacterial AOM and represents serous otitis media or viral upper respiratory infection. 1
• The most common error is treating serous otitis media (which is self-limited) as if it were acute bacterial otitis media. 1