What is the recommended dosage of Augmentin (amoxicillin/clavulanate) for adults?

Augmentin Adult Dosages

For adults with mild-to-moderate infections, use 500 mg/125 mg three times daily or 875 mg/125 mg twice daily, with the 875 mg formulation being preferred for respiratory tract infections. 1, 2

Standard Dosing Regimens

Mild-to-Moderate Infections

• 500 mg amoxicillin/125 mg clavulanate three times daily provides adequate coverage for most mild-to-moderate infections 1, 2
• 875 mg amoxicillin/125 mg clavulanate twice daily is the preferred dose for respiratory infections including acute bacterial rhinosinusitis, community-acquired pneumonia, and acute exacerbations of chronic bronchitis 1, 2
• Treatment duration is typically 7-10 days for most infections, though acute bacterial rhinosinusitis requires only 5-7 days 2

High-Dose Regimens for Resistant Pathogens

• 4 g amoxicillin/250 mg clavulanate daily (given as 2 g/125 mg twice daily) should be used when drug-resistant Streptococcus pneumoniae (DRSP) is suspected 1
• This high-dose regimen is indicated for patients with recent antimicrobial use (within 4-6 weeks), frequent daycare exposure, immunodeficiency, or moderate disease severity 1
• The calculated bacteriologic efficacy of high-dose amoxicillin/clavulanate (4 g/250 mg) is 99%, compared to 91-92% for standard-dose amoxicillin alone 1

Indication-Specific Dosing

Respiratory Tract Infections

• Acute bacterial rhinosinusitis: 500-875 mg twice daily for 5-7 days 1, 2
• Community-acquired pneumonia: 875 mg twice daily, with duration based on clinical response 1, 2
• Acute exacerbations of chronic bronchitis: 500-875 mg twice daily for at least 7 days 1, 2

Other Infections

• Recurrent streptococcal pharyngitis: 500 mg twice daily for 10 days 2
• Early Lyme disease with bacterial cellulitis: 500 mg three times daily for 14 days 2
• Urinary tract infections: 375 mg three times daily for 6-12 days 3, 4

Critical Dosing Considerations

Formulation Warning

• Never substitute two 250 mg tablets for one 500 mg tablet, as this results in excessive clavulanate dosing and increased gastrointestinal side effects 2
• The clavulanate component is fixed at 125 mg per dose in standard formulations, regardless of amoxicillin content 1

Treatment Failure Management

• If no improvement occurs after 72 hours on initial therapy, switch to a respiratory fluoroquinolone (levofloxacin, moxifloxacin, gatifloxacin) or high-dose amoxicillin/clavulanate if not already used 1
• Consider limitations in coverage of the initial antibiotic when selecting alternative therapy 1

Renal Impairment

• Dose reduction is required for patients with severe renal impairment (GFR <30 mL/min), though specific adjustments are not detailed in standard guidelines 5

Resistance Considerations

The choice between standard and high-dose regimens depends on local resistance patterns and patient risk factors. In areas where 25-50% of S. pneumoniae strains show penicillin resistance, high-dose regimens overcome this resistance through increased drug exposure 1. Similarly, with 50% of H. influenzae and 90-100% of M. catarrhalis producing beta-lactamase, the clavulanate component remains essential for adequate coverage 1.