What is the recommended dosage of Co-amoxiclav (amoxicillin/clavulanic acid) for pediatric patients?

Co-Amoxiclav Pediatric Dosing

For most pediatric infections, use high-dose amoxicillin-clavulanate at 90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day of clavulanate, divided into 2 doses (BID), which provides the optimal 14:1 ratio formulation. 1

Standard Dosing by Age and Weight

Age-Based Dosing (Using Standard Strength Suspensions)

For children without risk factors for resistant organisms:

• <1 year (1-12 months): 2.5 ml of 125/31 suspension three times daily 1
• 1-6 years: 5 ml of 125/31 suspension three times daily 1, 2
• 7-12 years: 5 ml of 250/62 suspension three times daily 1
• 12-18 years: 1 tablet (250/125) three times daily 1
• ≥40 kg: Dose as adults with 500/125 mg tablet every 12 hours 3

High-Dose Regimen (Preferred for Most Infections)

Use 90 mg/kg/day of amoxicillin component divided BID when:

• Age <2 years 1
• Daycare attendance 1
• Recent antibiotic use (within past 30 days) 1
• Incomplete Haemophilus influenzae type b vaccination (<3 injections) 1
• Geographic area with high pneumococcal resistance (>10% penicillin-resistant S. pneumoniae) 1
• Moderate to severe illness 1
• Concurrent purulent acute otitis media 1
• Treatment failure with standard-dose amoxicillin 4

This high-dose regimen uses the 400/57 mg per 5 mL or 200/28.5 mg per 5 mL suspension formulations to achieve the 14:1 ratio. 1, 3

Indication-Specific Dosing

Acute Otitis Media

• Standard dose: 45 mg/kg/day divided BID (using 200/28.5 or 400/57 formulation) 3
• High-dose: 90 mg/kg/day divided BID for risk factors listed above 4, 1
• Duration: 10 days 4, 3

Acute Bacterial Rhinosinusitis

• High-dose amoxicillin-clavulanate (90 mg/kg/day BID) is strongly recommended as first-line therapy in children 4
• Duration: 10-14 days 4

Community-Acquired Pneumonia

• <5 years with presumed bacterial pneumonia: 90 mg/kg/day in 2 doses 1
• <3 years without risk factors: Consider amoxicillin alone at 80-100 mg/kg/day in 3 divided doses first; add clavulanate if incomplete H. influenzae vaccination or concurrent purulent otitis media 1
• Duration: 10 days 1

Neonates and Infants <12 Weeks

• 30 mg/kg/day divided every 12 hours (based on amoxicillin component) 3
• Use 125/31.25 mg per 5 mL formulation (200/28.5 formulation has limited experience in this age group) 3

Critical Dosing Considerations

Why High-Dose Matters

• High-dose amoxicillin (80-90 mg/kg/day) exceeds the minimum inhibitory concentration for intermediately resistant S. pneumoniae and many highly resistant serotypes 1
• Using standard doses when high-dose therapy is indicated leads to treatment failure with resistant organisms 1
• Subtherapeutic doses fail to achieve adequate serum and tissue concentrations and promote antimicrobial resistance 1

Formulation Selection

• The 14:1 ratio formulation (90/6.4 mg/kg/day) causes less diarrhea than other amoxicillin-clavulanate preparations while maintaining efficacy 1
• BID dosing is associated with significantly less diarrhea than TID dosing 3
• Verify suspension concentration (125/31 vs 250/62 vs 200/28.5 vs 400/57) before calculating volume to avoid dosing errors 1

Maximum Doses

• Maximum single dose: 2 grams per dose regardless of weight 1
• Maximum daily dose: 4000 mg/day for children ≥5 years 1

Administration and Monitoring

Administration

• Take at the start of meals to enhance clavulanate absorption and minimize gastrointestinal intolerance 3
• Shake suspension well before each use 3
• Reconstituted suspension must be refrigerated and discarded after 10 days 3

Expected Clinical Response

• Clinical improvement should be evident within 48-72 hours 1, 2
• If no improvement or worsening after 72 hours, reassess diagnosis, consider atypical pathogens, evaluate for complications, or switch antibiotics 1

Common Pitfalls to Avoid

1. Do NOT use 250/125 tablets in children <40 kg - these contain 125 mg clavulanate (not 62.5 mg) and are not interchangeable with 250/62.5 chewable tablets 3

2. Do NOT underdose - an 80 mg total daily dose for a 5-year-old is grossly inadequate and promotes resistance 1

3. Do NOT prescribe antibiotics for viral URTIs - the vast majority of URTIs are viral and do not benefit from antibiotics 1

4. Ensure the child meets criteria for bacterial infection before prescribing: persistent symptoms >10 days without improvement, severe symptoms (fever ≥39°C with purulent nasal discharge for ≥3 consecutive days), or "double sickening" (worsening after initial improvement) 1

Adverse Effects

• Most common: Diarrhea, nausea, vomiting (gastrointestinal effects more common with higher clavulanate doses) 1, 3
• Less common: Rash, urticaria, hypersensitivity reactions 1, 2
• Monitor for allergic reactions, especially with first few doses 2