What is the recommended dose of Amoxiclav (amoxicillin/clavulanic acid) in adults?

Amoxicillin-Clavulanate (Amoxiclav) Dosing in Adults

For most adults with acute bacterial infections requiring amoxicillin-clavulanate, the standard dose is 875 mg/125 mg twice daily, but high-dose therapy (2000 mg/125 mg twice daily) should be used when treating patients at risk for resistant organisms or moderate-to-severe infections. 1

Standard-Dose Regimen

• 875 mg amoxicillin/125 mg clavulanate twice daily is the FDA-approved dose for severe infections and respiratory tract infections in adults 1
• This formulation should be taken at the start of meals to enhance clavulanate absorption and minimize gastrointestinal side effects 1
• Duration is typically 5-7 days for uncomplicated acute bacterial rhinosinusitis (ABRS) in adults 2

High-Dose Regimen: When to Escalate

Use 2000 mg/125 mg twice daily (or 90 mg/kg/day of amoxicillin component) when any of the following risk factors are present: 2

Risk Factors for Resistant Organisms:

• Antibiotic use within the past 4-6 weeks 2
• Age >65 years 2
• Recent hospitalization 2
• Immunocompromised status 2
• Geographic regions with high rates (>10%) of penicillin-nonsusceptible Streptococcus pneumoniae 2
• Close contact with daycare facilities 2
• Smoking or household smoker 2

Indicators of Moderate-to-Severe Infection:

• Moderate to severe symptoms of ABRS 2
• Fever ≥39°C (102°F) with systemic toxicity 2
• Frontal or sphenoidal sinusitis 2
• History of recurrent ABRS 2
• Comorbid conditions (diabetes, chronic cardiac/hepatic/renal disease) 2

Clinical Decision Algorithm

Step 1: Assess for penicillin allergy

• If true Type I hypersensitivity: use doxycycline or respiratory fluoroquinolone (levofloxacin/moxifloxacin) instead 2
• If non-Type I hypersensitivity: consider clindamycin plus third-generation cephalosporin 2

Step 2: If no allergy, determine dose based on risk stratification

• Low risk (no recent antibiotics, no comorbidities, mild symptoms): 875/125 mg twice daily 2, 1
• High risk (any factor listed above): 2000/125 mg twice daily 2

Step 3: Reassess at 72 hours

• If no improvement or worsening: switch to respiratory fluoroquinolone or consider further evaluation 2
• If improving: complete 5-7 day course for uncomplicated ABRS 2

Important Caveats

• Renal impairment: Patients with glomerular filtration rate <30 mL/min should NOT receive the 875 mg dose and require dose adjustment 1
• The 2000/125 mg formulation uses a pharmacokinetically enhanced, modified-release mechanism specifically designed for resistant pathogens 2, 3
• A recent 2021 randomized trial found no superiority of high-dose over standard-dose for clinically diagnosed acute sinusitis, but this contradicts guideline recommendations based on microbiologic data for resistant organisms 4. Guidelines still recommend high-dose therapy for the risk factors listed above 2
• Amoxicillin-clavulanate is preferred over amoxicillin alone in adults due to better coverage of beta-lactamase-producing organisms, though the evidence is weaker than in children 2
• Macrolides and trimethoprim-sulfamethoxazole should NOT be used due to high resistance rates (>40% for macrolides, 50% for TMP-SMX against S. pneumoniae) 2