What is the recommended dose and frequency of Augmentin (amoxicillin/clavulanate)?

Augmentin Dosing Recommendations

For most adult infections, Augmentin 875 mg/125 mg twice daily is the preferred oral regimen, providing optimal coverage for respiratory, skin/soft tissue, and urinary tract infections while minimizing gastrointestinal side effects compared to three-times-daily dosing. 1

Standard Adult Oral Dosing Regimens

Twice-Daily Dosing (Preferred for Most Infections)

• Augmentin 875 mg/125 mg twice daily is specifically recommended for respiratory infections including acute bacterial rhinosinusitis, community-acquired pneumonia, and acute exacerbations of chronic bronchitis 1
• This formulation is also indicated for skin and soft tissue infections, urinary tract infections, and animal or human bites 1
• The 875 mg formulation should be chosen for standard community-acquired infections and empiric therapy 1

Three-Times-Daily Dosing (Alternative Regimen)

• Augmentin 500 mg/125 mg three times daily provides adequate coverage for mild-to-moderate infections 1
• This regimen is recommended for acute bacterial rhinosinusitis when 10-day therapy is indicated 1
• For recurrent streptococcal pharyngitis in adults with multiple episodes, 500 mg twice daily for 10 days is recommended 1

Special Clinical Scenarios

• For animal or human bites: 500 mg/125 mg twice daily 1
• For early localized or disseminated Lyme disease with concurrent bacterial cellulitis: 500 mg three times daily for 14 days 1
• For chronic Group A streptococcal carriers with recurrent symptomatic episodes: 500 mg twice daily for 10 days 1

Intravenous Dosing

Standard IV Regimen

• For most serious infections including complicated intra-abdominal infections, severe respiratory infections, and severe skin/soft tissue infections: 1.2 g IV every 8 hours 1, 2
• Duration for intra-abdominal infections: 4-7 days with adequate source control 1
• Duration for skin and soft tissue infections: 7-10 days 2
• Duration for respiratory tract infections: 7-10 days depending on clinical response 2

Treatment Duration by Indication

• Uncomplicated acute bacterial rhinosinusitis: 5-7 days 1
• Streptococcal infections: minimum 10 days to prevent acute rheumatic fever 1
• Pneumonia: 5-7 days if afebrile for 48 hours and clinically stable 1
• Lyme disease with cellulitis: 14 days 1

Critical Dosing Considerations

Formulation Warnings

• Do NOT substitute two 250 mg tablets for one 500 mg tablet, as this results in excessive clavulanate dosing and increased gastrointestinal side effects 1
• IV dosing (1.2 g every 8 hours) should not be confused with oral dosing (875/125 mg twice daily), as these are different formulations with different pharmacokinetics 2

Renal Impairment

• Dosage adjustment is required in patients with severe renal impairment (GFR less than 30 mL/min), as amoxicillin is primarily eliminated by the kidney 3
• Amoxicillin may be removed from circulation by hemodialysis 3

Completion of Therapy

• Completing the full course of therapy is crucial to prevent treatment failure, resistance development, and complications such as acute rheumatic fever 1
• This applies regardless of clinical improvement 1

Pharmacokinetic Profile

• Peak blood levels occur 1-2 hours after oral administration 3
• The 875 mg tablet produces an AUC of 35.4 ± 8.1 mcg•hr/mL and a Cmax of 13.8 ± 4.1 mcg/mL 3
• Half-life of amoxicillin is 61.3 minutes 3
• Approximately 60% of an orally administered dose is excreted unchanged in urine within 6-8 hours 3
• Amoxicillin is approximately 20% protein-bound in blood serum 3

Common Pitfalls to Avoid

• Avoid using Augmentin as first-line therapy for uncomplicated Group A streptococcal pharyngitis—penicillin V or amoxicillin alone are preferred due to narrow spectrum, minimal adverse effects, and lower cost 1
• Reserve Augmentin for streptococcal carriers with recurrent symptomatic episodes, not routine acute pharyngitis 1
• For penicillin-allergic patients with acute strep pharyngitis, use cephalexin, clindamycin, azithromycin, or clarithromycin instead of Augmentin 1
• Consider avoiding aminoglycosides in combination with Augmentin when other nephrotoxic drugs are used or in renal dysfunction 4