Amoxicillin-Clavulanate
Brand names: Augmentin
Class: 💉 Penicillins, Cephalosporins & UTI Antibiotics
The NP-board angle on amoxicillin-clavulanate is knowing when plain amoxicillin is not enough. Adding clavulanate inhibits beta-lactamase and broadens coverage to include Haemophilus, Moraxella, anaerobes, and many oral flora. That makes Augmentin first-line for acute bacterial rhinosinusitis when antibiotics are indicated, chronic otitis media, dog/cat/human bite wounds, diabetic foot infections, and aspiration pneumonia. The trade-off is GI: clavulanate-induced diarrhea is the most common reason patients stop the drug. Take with food to blunt nausea. On the exam, the trigger phrases are bite wound, recurrent sinusitis after amoxicillin failure, or aspiration — that is the Augmentin question, not a fluoroquinolone.
✅ Indications
Sinusitis (if abx indicated), chronic otitis, aspiration pneumonia, dog/cat/human bites, diabetic foot infection.
⚙️ Mechanism of Action
Aminopenicillin + β-lactamase inhibitor — broader coverage (including anaerobes, β-lactamase-producing H. flu/Moraxella).
📏 Dosing
875/125 mg BID or 500/125 mg TID.
🚫 Contraindications
PCN allergy, cholestatic jaundice with prior amox-clav use.
⚠️ Adverse Effects
Diarrhea (HIGHER than amox alone — clavulanate), rash, cholestatic hepatitis, C. diff.
🔬 Monitoring
Clinical response; LFTs if prolonged course.
💎 Board Pearls
- 🐕 #1 choice for bite wounds (covers Pasteurella, Eikenella, anaerobes).
- 💩 Clavulanate = extra diarrhea — take with food helps.
- 🫁 2nd-line CAP when resistance suspected.
Practice Questions
A 38-year-old man presents to the clinic 10 hours after being bitten on the right hand by his indoor cat. The puncture wound at the base of the thumb is now mildly swollen, warm, and tender with expanding erythema. He has no drug allergies and is up to date on tetanus. Which of the following is the most appropriate first-line oral antibiotic?
Related Drugs in This Class
- Amoxicillin — Amoxil
- Cephalexin — Keflex
- Trimethoprim-Sulfamethoxazole — Bactrim, Septra, TMP-SMX
- Nitrofurantoin — Macrobid, Macrodantin
Sources
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