What is the appropriate volume of amoxicillin oral suspension for a 5‑year‑old female with acute otitis media weighing 15 kg?

Amoxicillin Dosing for a 5-Year-Old with Acute Otitis Media

For this 15 kg child, prescribe 1,200–1,350 mg of amoxicillin total daily dose, divided into two doses of 600–675 mg each (given every 12 hours), using high-dose amoxicillin oral suspension at 80–90 mg/kg/day. 1, 2, 3

Calculating the Exact Volume

The volume in milliliters depends entirely on the concentration of your amoxicillin suspension:

• If using 400 mg/5 mL suspension: Give 7.5–8.5 mL twice daily (total daily volume 15–17 mL) 1, 3
• If using 250 mg/5 mL suspension: Give 12–13.5 mL twice daily (total daily volume 24–27 mL) 1, 3
• If using 200 mg/5 mL suspension: Give 15–17 mL twice daily (total daily volume 30–34 mL) 1, 3

The 400 mg/5 mL concentration is strongly preferred because it minimizes volume and improves adherence. 4

Treatment Duration

Prescribe a 7-day course for this 5-year-old if symptoms are mild-to-moderate (otalgia <48 hours and fever <39°C). 2

Extend to a full 10-day course if the child has severe symptoms: moderate-to-severe otalgia, otalgia ≥48 hours, or fever ≥39°C (102.2°F). 1, 2

When to Use Amoxicillin-Clavulanate Instead

Switch to amoxicillin-clavulanate (90 mg/kg/day amoxicillin component + 6.4 mg/kg/day clavulanate, divided BID) if any of the following apply: 1, 2, 3

• The child received amoxicillin within the past 30 days 1, 2
• Concurrent purulent conjunctivitis is present (suggests Haemophilus influenzae) 1, 2
• The child attends daycare or lives in an area with high prevalence of β-lactamase-producing organisms 1

For this scenario, the 14:1 amoxicillin-to-clavulanate ratio formulation causes significantly less diarrhea than older 7:1 formulations while maintaining efficacy. 1, 5

Pain Management (Critical First Step)

Immediately administer weight-based acetaminophen or ibuprofen regardless of antibiotic choice, as antibiotics provide zero symptomatic relief in the first 24 hours. 2

Continue analgesics throughout the acute phase, because even after 3–7 days of antibiotics, 30% of young children still have persistent pain or fever. 2

Reassessment Protocol

Re-evaluate at 48–72 hours if symptoms worsen or fail to improve. 1, 2, 3

• If amoxicillin fails, switch to amoxicillin-clavulanate (90 mg/kg/day amoxicillin component) 1, 2, 3
• If amoxicillin-clavulanate fails, administer intramuscular ceftriaxone 50 mg/kg once daily for 3 consecutive days (superior to single-dose regimen) 1, 2

Common Pitfalls to Avoid

Do not use standard-dose amoxicillin (40–45 mg/kg/day)—it achieves inadequate middle ear fluid concentrations against intermediately resistant Streptococcus pneumoniae, which accounts for approximately 87% of pneumococcal isolates when high-dose therapy is used versus only 83% with standard dosing. 1, 6

Do not prescribe azithromycin or other macrolides as first-line therapy—pneumococcal macrolide resistance exceeds 40% in the United States, resulting in bacterial failure rates of 20–25%. 1

Twice-daily dosing is equally effective as three-times-daily dosing and significantly improves adherence by reducing family-perceived scheduling difficulties. 1, 4

Expected Post-Treatment Course

Middle ear effusion persists in 60–70% of children at 2 weeks after successful treatment, declining to 40% at 1 month and 10–25% at 3 months. 1, 2

This post-treatment effusion (otitis media with effusion) requires monitoring but NOT additional antibiotics unless it persists >3 months with documented hearing loss. 1, 2