What is the recommended dose of coamoxiclav (amoxicillin/clavulanic acid) for pediatric patients?

Pediatric Dosing of Co-amoxiclav (Amoxicillin/Clavulanate)

For most pediatric infections requiring co-amoxiclav, use the high-dose regimen of 90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day of clavulanate, divided into two doses (BID), for 10 days. 1, 2

Standard High-Dose Regimen (Preferred for Most Indications)

The high-dose formulation (90 mg/kg/day) provides a 14:1 ratio of amoxicillin to clavulanate and is the recommended first-line regimen for children ≥3 months with respiratory tract infections, acute otitis media, and acute bacterial rhinosinusitis. 1, 3

Weight-Based Dosing Table (High-Dose 600 mg/42.9 mg per 5 mL Suspension)

According to FDA labeling, for children ≥3 months using the 600 mg/5 mL formulation 2:

• 8 kg: 3.0 mL twice daily
• 12 kg: 4.5 mL twice daily
• 16 kg: 6.0 mL twice daily
• 20 kg: 7.5 mL twice daily
• 24 kg: 9.0 mL twice daily
• 28 kg: 10.5 mL twice daily
• 32 kg: 12.0 mL twice daily
• 36 kg: 13.5 mL twice daily

Alternative Age-Based Dosing (Standard-Dose Formulations)

For standard-dose formulations when high-dose is not indicated 1:

• <1 year (1-12 months): 2.5 mL of 125/31 suspension three times daily
• 1-6 years: 5 mL of 125/31 suspension three times daily
• 7-12 years: 5 mL of 250/62 suspension three times daily
• 12-18 years: 1 tablet (250/125) three times daily

Indications for High-Dose Therapy

High-dose co-amoxiclav (90 mg/kg/day) is specifically indicated for children with any of the following risk factors 1:

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

Specific Clinical Scenarios

Community-Acquired Pneumonia

• Children <5 years: 90 mg/kg/day of amoxicillin component in 2 doses for 10 days 1
• Children ≥5 years: 90 mg/kg/day in 2 doses (maximum 4000 mg/day) for 10 days 1
• Note: For children <3 years without risk factors for resistant organisms, amoxicillin alone at 80-100 mg/kg/day in 3 divided doses is preferred over co-amoxiclav 1

Acute Otitis Media

• High-dose regimen (90 mg/kg/day in 2 doses) for 10 days is recommended for severe AOM, bilateral AOM in children 6-23 months, or recent antibiotic exposure 1, 4
• This regimen achieves middle ear fluid concentrations adequate to overcome penicillin-resistant S. pneumoniae 1

Acute Bacterial Rhinosinusitis

• 90 mg/kg/day divided BID for 10-14 days as first-line therapy 1

Critical Formulation Considerations

The 600 mg/42.9 mg per 5 mL suspension is NOT interchangeable with other co-amoxiclav formulations 2:

• 600 mg/5 mL contains 42.9 mg clavulanate per 5 mL
• 200 mg/5 mL contains 28.5 mg clavulanate per 5 mL
• 400 mg/5 mL contains 57 mg clavulanate per 5 mL

Always verify the suspension concentration before calculating volume to avoid potentially dangerous dosing errors. 1

Treatment Duration and Monitoring

• Standard duration: 10 days for most respiratory infections, AOM, and bacterial pneumonia 1, 4
• Clinical improvement should occur within 48-72 hours; if no improvement or worsening occurs, reassess diagnosis and consider atypical pathogens or complications 1
• Complete the full prescribed course even if symptoms improve before completion 5

Intravenous Dosing

For severe infections requiring IV therapy 1:

• 30 mg/kg three times daily IV for all pediatric ages

Maximum Doses

• Maximum single dose: 2 grams per dose regardless of weight 1
• Maximum daily dose: 4000 mg (4 g) per day of amoxicillin component 1, 5

Administration Guidelines

• Administer at the start of meals to minimize gastrointestinal intolerance and enhance clavulanate absorption 2
• Shake suspension well before each use 2
• Refrigerate reconstituted suspension; stable for 10 days 2

Common Adverse Effects

• Diarrhea is the most common adverse effect, occurring less frequently with twice-daily dosing compared to three-times-daily regimens 1, 4
• Other effects include nausea, vomiting, and rash 1
• The high-dose 14:1 ratio formulation causes less diarrhea than other co-amoxiclav preparations while maintaining efficacy 1

Critical Pitfalls to Avoid

1. Using standard doses when high-dose therapy is indicated leads to treatment failure with resistant organisms 1
2. Subtherapeutic dosing fails to achieve adequate tissue concentrations and promotes antimicrobial resistance 1
3. Most upper respiratory tract infections are viral—ensure the child meets criteria for bacterial infection (persistent symptoms >10 days, severe symptoms, or "double sickening") before prescribing antibiotics 1
4. Do not substitute different co-amoxiclav formulations without recalculating doses based on both amoxicillin and clavulanate content 2

Renal Impairment

In children with renal insufficiency, prolong the dosing interval according to creatinine clearance to avoid drug accumulation, as both amoxicillin and clavulanic acid are renally eliminated 1