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# Amoxicillin-Clavulanate (Augmentin)
## Overview
Amoxicillin-clavulanate is a fixed-dose combination of a penicillin-class antibiotic (amoxicillin) and a beta-lactamase inhibitor (clavulanate). The addition of clavulanate extends the spectrum of activity to include beta-lactamase-producing bacteria.
## Primary Indications
* Acute bacterial rhinosinusitis
* Community-acquired pneumonia
* Skin and skin structure infections
* Bite wounds (human or animal)
* Acute otitis media (particularly when resistant *S. pneumoniae* is suspected)
* Recurrent or complicated urinary tract infections
## Adult Dosing
Standard dosing is typically based on the amoxicillin component:
* **Mild to moderate infections:** 500 mg amoxicillin every 8 or 12 hours OR 875 mg amoxicillin every 12 hours.
* **Severe infections:** 875 mg amoxicillin every 8 hours.
* *Note:* Use extended-release formulations (e.g., 2000 mg) for specific indications like community-acquired pneumonia; do not substitute two 1000 mg tablets for one 2000 mg extended-release tablet due to high clavulanate content.
## Pediatric Dosing
* **Standard dose:** 25–45 mg/kg/day (based on amoxicillin component) divided every 12 hours.
* **Acute otitis media/Severe infections:** 80–90 mg/kg/day divided every 12 hours.
* *Maximum:* Do not exceed the adult maximum dose for the specific formulation. Use formulations with appropriate amoxicillin:clavulanate ratios (e.g., 7:1 or 14:1) to minimize diarrhea caused by excess clavulanate.
## Dose Adjustments
* **Renal Impairment:** Reduce frequency or avoid use if CrCl < 30 mL/min. DO NOT use the 875 mg tablet in patients with severe renal impairment (CrCl < 30 mL/min).
* **Hepatic Impairment:** Use with caution.
## Contraindications
* History of serious hypersensitivity (e.g., anaphylaxis) to penicillins.
* History of cholestatic jaundice or hepatic dysfunction associated with previous use of amoxicillin-clavulanate.
## Adverse Effects
* **Most common:** Diarrhea (frequently clavulanate-related), nausea, and vomiting.
* **Serious:** *Clostridioides difficile*-associated diarrhea, hypersensitivity reactions (rash, urticaria, anaphylaxis), and drug-induced hepatitis/cholestatic jaundice (more likely with prolonged use in older adults).
## Key Drug Interactions
* **Methotrexate:** May increase methotrexate levels and toxicity.
* **Warfarin:** May enhance the anticoagulant effect by altering gut flora (vitamin K synthesis). Monitor INR.
* **Oral Contraceptives:** Potential for reduced efficacy (secondary to gut flora alteration); advise additional barrier protection during treatment.
## Monitoring
* Monitor for signs of allergic reactions (e.g., rash, swelling).
* Monitor renal function in patients with pre-existing impairment.
* Assess for persistent diarrhea (rule out *C. diff*).
* For prolonged courses: Monitor LFTs and CBC.
## Clinical Pearls
* **Formulation Warning:** 250 mg tablets and 250 mg chewable tablets contain the same amount of clavulanate; they are NOT interchangeable.
* **GI Tolerance:** Administer with a meal or snack to minimize gastrointestinal upset.
* **Beta-lactamase spectrum:** The addition of clavulanate provides coverage against *H. influenzae*, *M. catarrhalis*, *S. aureus* (methicillin-sensitive), and many anaerobes. It does not provide coverage for MRSA or *Pseudomonas aeruginosa*.
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**Educational Disclaimer:** This information is for educational purposes only. Always verify drug doses, contraindications, and drug interactions with the most current version of your clinical prescribing resource (e.g., Lexicomp, UpToDate) or institutional pharmacy guidelines before prescribing or administering medication.
