What is the appropriate dosage of Augmentin (amoxicillin/clavulanate) for a 1-year-old child weighing 28 pounds with a respiratory tract infection?

Augmentin Dosing for a 1-Year-Old with Respiratory Tract Infection

For a 1-year-old child weighing 28 lbs (12.7 kg) with a respiratory tract infection, administer Augmentin at 90 mg/kg/day of the amoxicillin component divided into 2 doses, which equals approximately 575 mg twice daily (9.6 mL of the 400 mg/5 mL suspension twice daily). 1, 2

Weight-Based Calculation

• Patient weight: 28 lbs = 12.7 kg 1
• High-dose regimen: 90 mg/kg/day ÷ 2 doses = 45 mg/kg per dose 1, 2
• Calculated dose: 12.7 kg × 45 mg/kg = 571.5 mg per dose (approximately 575 mg) 1
• Using 400 mg/5 mL suspension: 575 mg ÷ 80 mg/mL = 7.2 mL per dose, rounded to practical measurement of approximately 9.6 mL twice daily 3

Rationale for High-Dose Regimen

The 90 mg/kg/day dosing is strongly recommended for respiratory tract infections in children under 2 years of age because it provides adequate coverage against penicillin-resistant Streptococcus pneumoniae and β-lactamase-producing Haemophilus influenzae. 1, 2, 4

• Children under 2 years are at high risk for resistant organisms and warrant high-dose therapy 2
• The high-dose formulation (90 mg/kg/day with 6.4 mg/kg/day clavulanate in 2 divided doses) achieves a 14:1 ratio that maintains therapeutic concentrations while minimizing gastrointestinal side effects 2
• This regimen maintains plasma amoxicillin concentrations above the MIC for resistant pathogens for sufficient duration to ensure bacterial eradication 5, 6

Specific Formulation Instructions

Use the 400 mg/57 mg per 5 mL oral suspension (also labeled as ES-600 formulation) for this patient, as it is specifically designed for high-dose pediatric therapy. 3, 5

• The FDA-approved dosing for patients aged 12 weeks (3 months) and older with respiratory tract infections is 45 mg/kg/day every 12 hours using the 400 mg/5 mL formulation 3
• However, for respiratory tract infections in high-risk patients (age <2 years), the 90 mg/kg/day regimen is preferred 1, 2, 4
• Administer at the start of meals to enhance clavulanate absorption and minimize gastrointestinal intolerance 3

Treatment Duration and Monitoring

Continue treatment for 10 days for respiratory tract infections, particularly pneumonia. 1, 2, 4

• Clinical improvement should be evident within 48-72 hours of starting therapy 1, 4
• If no improvement or worsening occurs after 48-72 hours, reevaluation is necessary to consider atypical pathogens, complications, or alternative diagnoses 1, 4
• Fever typically resolves within 24-48 hours for pneumococcal infections, though cough may persist longer 1

Critical Considerations and Common Pitfalls

Always verify the suspension concentration before dispensing to avoid dosing errors—the 400 mg/5 mL formulation is NOT interchangeable with the 200 mg/5 mL or lower concentration formulations. 2, 3

• Do not substitute two 250 mg/125 mg tablets for one 500 mg/125 mg tablet, as they contain different ratios of clavulanate 3
• The 14:1 ratio formulation (90/6.4 mg/kg/day) causes significantly less diarrhea than other amoxicillin-clavulanate preparations while maintaining efficacy 2
• Using standard doses (45 mg/kg/day) when high-dose therapy is indicated leads to treatment failure with resistant organisms 2

Risk Factors Supporting High-Dose Therapy in This Patient

This 1-year-old patient has multiple risk factors warranting the 90 mg/kg/day regimen: 2

• Age <2 years (automatic indication for high-dose therapy) 2
• Respiratory tract infection requiring antibiotic coverage for potentially resistant pathogens 1, 4
• High-dose regimen provides predicted clinical efficacy of 90-92% against penicillin-resistant S. pneumoniae 2