What is the appropriate amoxicillin‑clavulanate dosage for a 19‑lb (≈8.6 kg) infant?

Amoxicillin-Clavulanate Dosing for 19 lb (8.6 kg) Infant

For a 19 lb (8.6 kg) infant aged 3 months or older, administer amoxicillin-clavulanate 45 mg/kg/day (based on amoxicillin component) divided every 12 hours for moderate infections like otitis media, sinusitis, or lower respiratory tract infections, which equals approximately 193 mg amoxicillin twice daily. 1

Specific Dosing Calculation

• Weight: 19 lbs = 8.6 kg
• Standard dose for moderate infections: 45 mg/kg/day divided every 12 hours 1
• Total daily dose: 8.6 kg × 45 mg/kg = 387 mg/day
• Per dose (every 12 hours): 193 mg amoxicillin per dose

Formulation Selection

Use the 200 mg/5 mL or 400 mg/5 mL oral suspension formulation, as the FDA label specifically recommends the every-12-hour regimen because it is associated with significantly less diarrhea. 1

• For 193 mg per dose using 200 mg/5 mL suspension: Give approximately 4.8 mL every 12 hours
• The 125 mg/5 mL suspension is reserved for neonates and infants under 3 months 1

Dosing Based on Infection Severity

For Less Severe Infections:

• 25 mg/kg/day every 12 hours 1
• For 8.6 kg infant: 107.5 mg per dose (approximately 2.7 mL of 200 mg/5 mL suspension)

For More Severe Infections or High-Risk Situations:

Use high-dose amoxicillin-clavulanate (80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate) in 2 divided doses if the infant: 2

• Is younger than 2 years old
• Attends daycare
• Has received antibiotics within the past 30 days
• Has moderate to severe illness
• Lives in an area with high prevalence of resistant Streptococcus pneumoniae (>10%)

For 8.6 kg infant at high dose (90 mg/kg/day): 387 mg per dose every 12 hours

Critical Prescribing Considerations

The clavulanate ratio matters significantly for both efficacy and tolerability. The standard formulation provides 6.4 mg/kg/day of clavulanate with high-dose regimens, though recent research suggests lower clavulanate concentrations (2.85-3.2 mg/kg/day) may reduce diarrhea while maintaining efficacy. 3

Common Pitfalls to Avoid:

• Never substitute two 250 mg/125 mg tablets for one 500 mg/125 mg tablet - they contain different clavulanate ratios and are not equivalent 1
• Do not use 250 mg/125 mg tablets in children under 40 kg due to inappropriate amoxicillin-to-clavulanate ratios 1
• Administer at the start of meals to enhance clavulanate absorption and minimize gastrointestinal intolerance 1

Duration of Therapy

For acute otitis media, treat for 10 days. 1 For acute bacterial sinusitis, the American Academy of Pediatrics recommends continuing therapy for 7 days after the patient becomes symptom-free, resulting in a minimum 10-day course. 2

Age-Specific Guidance

If the infant is under 3 months old (<12 weeks), use 30 mg/kg/day divided every 12 hours with the 125 mg/5 mL suspension specifically. 1 The 200 mg/5 mL formulation has limited experience in this age group and should be avoided.