What is the recommended dosage of amoxicillin-clavulanate (Augmentin) for adults and pediatric patients with normal and impaired renal function?

Amoxicillin-Clavulanate Dosing Recommendations

For adults with respiratory infections, use 875 mg/125 mg twice daily for standard cases or 2000 mg/125 mg twice daily when antibiotic resistance is likely; for children, use 45 mg/kg/day (standard) or 80-90 mg/kg/day (high-dose) of the amoxicillin component divided into two daily doses. 1, 2

Adult Dosing Regimens

Standard-Dose Therapy

• 500 mg/125 mg every 12 hours or 250 mg/125 mg every 8 hours for mild to moderate infections 2
• 875 mg/125 mg every 12 hours or 500 mg/125 mg every 8 hours for more severe infections and respiratory tract infections 1, 2
• The 625 mg formulation (500 mg amoxicillin/125 mg clavulanate) three times daily is recommended for bronchiectasis exacerbations and non-severe pneumonia 1

High-Dose Therapy (2000 mg/125 mg twice daily)

Use high-dose therapy when any of these risk factors are present: 1, 3

• Recent antibiotic use within the past 4-6 weeks
• Previous antibiotic treatment failure
• Close contact with healthcare environments or daycare facilities
• Moderate to severe infection (high fever ≥39°C or systemic toxicity)
• Geographic areas with >10% penicillin-resistant Streptococcus pneumoniae prevalence
• Age >65 years
• Comorbidities (diabetes, chronic cardiac/pulmonary/hepatic/renal disease)
• Immunocompromised status
• Smoking or exposure to smokers
• Frontal or sphenoidal sinusitis

The high-dose formulation achieves adequate serum concentrations to eradicate penicillin-resistant S. pneumoniae with MICs up to 4-8 mg/L, with predicted clinical efficacy of 90-92% 1, 3

Pediatric Dosing

Standard-Dose Regimen (Children ≥12 weeks)

• 45 mg/kg/day every 12 hours or 40 mg/kg/day every 8 hours for more severe infections (otitis media, sinusitis, lower respiratory tract infections) 3, 2
• 25 mg/kg/day every 12 hours or 20 mg/kg/day every 8 hours for less severe infections 3, 2
• The every 12-hour regimen is preferred as it causes significantly less diarrhea 2

High-Dose Regimen

Use 80-90 mg/kg/day of amoxicillin with 6.4 mg/kg/day of clavulanate divided into 2 doses when: 1, 3

• Age <2 years
• Daycare attendance
• Recent antibiotic treatment within 30 days
• Concurrent conjunctivitis (otitis-conjunctivitis syndrome)
• Geographic areas with >10% penicillin-resistant S. pneumoniae
• Pneumonia not responding to amoxicillin alone
• Previous treatment failure

The 14:1 ratio in high-dose formulations causes less diarrhea than other amoxicillin-clavulanate preparations 1

Neonates and Infants <12 weeks

• 30 mg/kg/day divided every 12 hours based on the amoxicillin component 2
• Use the 125 mg/5 mL oral suspension (experience with 200 mg/5 mL formulation is limited in this age group) 2

Weight-Based Considerations

• Children weighing ≥40 kg should be dosed according to adult recommendations 2
• Maximum amoxicillin dose is 4000 mg/day 1

Renal Impairment Dosing

Adjust doses based on glomerular filtration rate (GFR): 2

• GFR <30 mL/min: Do not use the 875 mg/125 mg dose
• GFR 10-30 mL/min: 500 mg/125 mg or 250 mg/125 mg every 12 hours (depending on infection severity)
• GFR <10 mL/min: 500 mg/125 mg or 250 mg/125 mg every 24 hours (depending on infection severity)
• Hemodialysis patients: 500 mg/125 mg or 250 mg/125 mg every 24 hours, with an additional dose during and at the end of dialysis 2

Treatment Duration

Adults

• Acute bacterial rhinosinusitis: 5-7 days 1, 3
• Respiratory infections: 7-10 days (may extend to 14 days based on clinical response) 1, 3
• Community-acquired pneumonia: 7-10 days 1
• Uncomplicated UTIs: 3-7 days 3

Pediatrics

• Acute otitis media: 10 days 2
• Acute bacterial rhinosinusitis: 10-14 days (longer than adults) 1, 3
• Non-severe pneumonia: 5 days 1

Administration Guidelines

• Take at the start of meals to enhance clavulanate absorption and minimize gastrointestinal intolerance 2
• Evaluate clinical response within 48-72 hours; if no improvement, consider changing antibiotics or reevaluating the diagnosis 1, 3
• Switch from IV to oral formulation as soon as clinically appropriate 1

Critical Dosing Pitfalls to Avoid

Do not substitute formulations incorrectly: 2

• Two 250 mg/125 mg tablets ≠ one 500 mg/125 mg tablet (both contain 125 mg clavulanate, but different amoxicillin amounts)
• The 250 mg/125 mg tablet ≠ 250 mg/62.5 mg chewable tablet (different clavulanate content)
• The 250 mg/125 mg tablet should not be used until the child weighs ≥40 kg due to different amoxicillin:clavulanate ratios

Avoid underdosing in high-resistance areas: Use high-dose formulations (2000 mg/125 mg twice daily for adults or 90 mg/kg/day for children) in areas with >10% penicillin-resistant S. pneumoniae prevalence 1, 3

Do not routinely cover MRSA in initial empiric therapy for respiratory infections—current evidence does not support this approach 1, 4