What is the recommended dosing of amoxicillin (amoxicillin) for pneumonia?

Amoxicillin Dosing for Pneumonia

For healthy adults without comorbidities, amoxicillin 1 gram three times daily (every 8 hours) for 5-7 days is the first-line treatment for community-acquired pneumonia. 1

Adult Dosing by Clinical Setting

Outpatient Treatment - Healthy Adults (No Comorbidities)

• Amoxicillin 1 gram orally every 8 hours (three times daily) is the preferred first-line therapy, with strong recommendation and moderate quality evidence 2, 1
• Treatment duration should be 5-7 days for uncomplicated cases 1
• Alternative options include doxycycline 100 mg twice daily or macrolides (only if local pneumococcal macrolide resistance is documented <25%) 1

Outpatient Treatment - Adults with Comorbidities

• Amoxicillin monotherapy is insufficient and should NOT be used in patients with comorbidities (COPD, heart disease, diabetes, renal disease) 1
• Combination therapy is required: amoxicillin/clavulanate 875 mg/125 mg twice daily PLUS azithromycin 500 mg day 1, then 250 mg daily for 5-7 days 1
• Alternative combination: amoxicillin/clavulanate 500 mg/125 mg three times daily PLUS a macrolide 1
• High-dose formulation: amoxicillin/clavulanate 2000 mg/125 mg twice daily for drug-resistant S. pneumoniae 3, 4

Inpatient Treatment (Non-ICU)

• Beta-lactam (ampicillin-sulbactam, ceftriaxone, or cefotaxime) PLUS macrolide is the standard regimen 1
• Amoxicillin/clavulanate should be combined with azithromycin 500 mg daily or clarithromycin 500 mg twice daily 3

Pediatric Dosing (Children >6 months)

Standard Dosing for Uncomplicated CAP

• Amoxicillin 75-100 mg/kg/day divided into 3 doses for beta-lactamase negative H. influenzae 2
• Amoxicillin 50-75 mg/kg/day divided into 2 doses for Group A Streptococcus 2
• Treatment duration: 5 days is as effective as 10 days for uncomplicated pneumonia in children 5, 6

High-Dose Pediatric Regimens

• Amoxicillin/clavulanate 90 mg/kg/day (amoxicillin component) divided into 2 doses for drug-resistant S. pneumoniae or beta-lactamase producing organisms 2, 4
• Alternative: amoxicillin/clavulanate 45 mg/kg/day divided into 3 doses 2

Critical Decision Points

When to Use High-Dose Amoxicillin

Use high-dose formulations (1 gram every 8 hours in adults; 90 mg/kg/day in children) when:

• Geographic area has pneumococcal macrolide resistance >25% 3
• Recent antibiotic use within 3 months 3
• Age >65 years or <2 years 3
• Suspected penicillin-resistant S. pneumoniae (MIC ≥2 mg/L) 3
• Presence of comorbidities 3

When Amoxicillin Should NOT Be Used

• Never use amoxicillin monotherapy in patients with comorbidities - combination therapy is mandatory 1
• Avoid in patients requiring hospitalization without adding macrolide coverage 1
• Do not use if patient received amoxicillin within past 90 days - select different antibiotic class 1

Treatment Duration and Monitoring

• Standard duration: 5-7 days for most cases of uncomplicated CAP 1, 3
• Ensure at least 48 hours of clinical stability (afebrile, improving symptoms) before discontinuing therapy 3
• Fever should resolve within 2-3 days; if no improvement by day 2-3, reassess for complications 1
• Extended treatment (14-21 days) required ONLY for: Legionella, Staphylococcus aureus, or gram-negative enteric bacilli 1

Common Pitfalls to Avoid

• Do not use amoxicillin alone in patients with any comorbidity - this is the most common error and leads to treatment failure 1
• Do not automatically extend treatment beyond 5-7 days unless specific pathogens (Legionella, S. aureus) are identified 1
• Do not use macrolide monotherapy in areas with pneumococcal resistance ≥25% or in patients with recent antibiotic exposure 1
• In children, do not routinely prescribe 10-day courses when 5 days is equally effective for uncomplicated cases 5, 6