What is the maximum recommended dose of co‑amoxiclav suspension (457 mg per 5 mL) for children, expressed in mg/kg and volume per dose?

Maximum Dose for Co-Amoxiclav 457mg/5ml Suspension in Children

The maximum recommended dose of co-amoxiclav 457mg/5ml suspension (high-dose formulation) is 90 mg/kg/day of the amoxicillin component, divided into two doses, with an absolute maximum daily dose of 4000 mg (4 g) of amoxicillin regardless of weight. 1

Weight-Based Dosing Algorithm

For the 457mg/5ml suspension (which contains 400mg amoxicillin + 57mg clavulanate per 5ml, providing a 14:1 ratio):

• Standard high-dose regimen: 90 mg/kg/day of amoxicillin divided into two doses (every 12 hours) 1
• Maximum single dose: 2000 mg (2 g) of amoxicillin per administration 1
• Maximum daily dose: 4000 mg (4 g) of amoxicillin per day 1, 2

Practical Volume Calculation

To calculate the volume per dose:

1. Multiply child's weight (kg) × 45 mg/kg = mg per dose
2. Divide by 80 (since 5ml contains 400mg, or 80mg per ml)
3. Result = ml per dose, given twice daily

Example: For a 20 kg child:

• 20 kg × 45 mg/kg = 900 mg per dose
• 900 ÷ 80 = 11.25 ml per dose
• Give 11.25 ml twice daily (total daily dose = 1800 mg)

Indications for High-Dose Regimen

The 90 mg/kg/day regimen is specifically indicated when any of these risk factors are present: 1

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

Age-Based Alternative Dosing (Lower-Strength Formulations)

If using standard-strength suspensions rather than the 457mg/5ml formulation: 3, 1

• < 1 year (1-12 months): 2.5 ml/kg of 125/31 suspension three times daily 3, 1
• 1-6 years: 5 ml of 125/31 suspension three times daily 3, 1
• 7-12 years: 5 ml of 250/62 suspension three times daily 3, 1

Critical Dosing Considerations

Maximum Dose Limits

• Never exceed 2000 mg amoxicillin per single dose, even in children weighing > 44 kg 1
• For children ≥ 40 kg, use adult dosing regimens rather than weight-based calculations 1, 2

Treatment Duration

• Standard respiratory infections: 7-10 days 1
• Pneumonia: 10 days minimum 1
• Continue for 48-72 hours after complete symptom resolution 1

Monitoring for Response

• Clinical improvement should be evident within 48-72 hours of starting therapy 1
• If no improvement or worsening after 72 hours, reassess diagnosis and consider alternative pathogens or complications 1

Common Pitfalls to Avoid

• Suspension concentration errors: The 457mg/5ml formulation is NOT the same as 125/31 or 250/62 suspensions—verify the concentration before calculating volume 1
• Underdosing: Using standard doses (45 mg/kg/day) when high-dose therapy (90 mg/kg/day) is indicated leads to treatment failure with resistant organisms 1
• Exceeding maximum daily dose: Even for very heavy children, never exceed 4000 mg/day total amoxicillin 1, 2
• Inappropriate three-times-daily dosing: The 457mg/5ml high-dose formulation is designed for twice-daily administration; three-times-daily dosing would result in excessive clavulanate and increased diarrhea 1

Renal Impairment Adjustment

• In children with established renal insufficiency, prolong the dosing interval according to creatinine clearance to avoid drug accumulation 1
• Dose reduction is essential due to renal elimination of both amoxicillin and clavulanate 1