Liquid Augmentin Dosing in Adults
No—liquid Augmentin is not dosed the same as tablets for adults; you must match the total daily amoxicillin and clavulanate content of the tablet regimen, which requires careful suspension volume calculations to avoid underdosing or excessive clavulanate.
Core Dosing Principle
The FDA label explicitly states that adults who have difficulty swallowing may substitute suspension for tablets only by matching both the amoxicillin and clavulanate components—not by simple milligram-for-milligram conversion. 1
Standard Adult Tablet Regimens
- Mild-to-moderate infections: 500 mg amoxicillin/125 mg clavulanate every 12 hours. 1
- Respiratory infections or more severe disease: 875 mg amoxicillin/125 mg clavulanate every 12 hours. 1, 2
Equivalent Liquid Substitutions (FDA-Approved)
When tablets cannot be swallowed:
- To replace one 500 mg/125 mg tablet: Use 10 mL of the 250 mg/62.5 mg per 5 mL suspension (providing 500 mg amoxicillin and 125 mg clavulanate per dose). 1
- To replace one 875 mg/125 mg tablet: Use 10 mL of the 400 mg/57 mg per 5 mL suspension (providing 800 mg amoxicillin and 114 mg clavulanate—the closest available match). 1
Critical Prescribing Pitfalls
Non-Interchangeable Formulations
- Two 250 mg/125 mg tablets ≠ one 500 mg/125 mg tablet because both contain 125 mg clavulanate; doubling the 250 mg tablet delivers 250 mg excess clavulanate, increasing diarrhea risk (reported in 40–43 % of patients at standard clavulanate doses). 1, 3
- The 250 mg/125 mg tablet ≠ the 250 mg/62.5 mg chewable tablet due to differing clavulanate content (125 mg vs. 62.5 mg). 1
Clavulanate Dose Ceiling
- Adult formulations restrict clavulanate to 125 mg per dose (375 mg/day maximum) because higher amounts cause intolerable gastrointestinal adverse effects—nausea, vomiting, and diarrhea—without added clinical benefit. 4, 5
- Prescribing liquid volumes that exceed this clavulanate threshold (e.g., 15 mL of 250/62.5 suspension to match 875 mg amoxicillin) delivers 187.5 mg clavulanate per dose, violating FDA tolerability limits. 1, 4
High-Dose Regimens for Resistant Pathogens
When to Use High-Dose Therapy
- Indications: Recent antibiotic use (past 4–6 weeks), age > 65 years, daycare exposure, moderate-to-severe symptoms, comorbidities, immunocompromised status, or geographic areas with > 10 % penicillin-resistant Streptococcus pneumoniae. 6
- Dose: Amoxicillin 2 g + clavulanate 125 mg twice daily (4 g/250 mg per day total). 7, 6
Liquid Equivalent for High-Dose Regimen
- No FDA-approved adult suspension delivers 2 g amoxicillin with only 125 mg clavulanate per dose. The 400 mg/57 mg per 5 mL suspension would require 25 mL per dose (providing 2 g amoxicillin but 285 mg clavulanate—more than double the tolerable limit). 1, 4
- Solution: Adults requiring high-dose therapy who cannot swallow tablets should receive parenteral ceftriaxone 1–2 g IV/IM daily for 5 days as the guideline-recommended alternative. 6
Reassessment Timeline
- At 3–5 days: If no clinical improvement, escalate to high-dose amoxicillin-clavulanate (if not already prescribed) or switch to a respiratory fluoroquinolone. 6
- At 7 days: Persistent or worsening symptoms require diagnostic reconsideration, imaging (CT scan), and possible ENT referral. 6