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# Amoxicillin-Clavulanate (Augmentin)
## Overview
Amoxicillin-clavulanate is a fixed-dose combination antibiotic consisting of a semi-synthetic penicillin (amoxicillin) and a beta-lactamase inhibitor (clavulanate potassium). The addition of clavulanate expands the spectrum of activity to include beta-lactamase-producing strains of *S. aureus*, *H. influenzae*, *M. catarrhalis*, and certain anaerobes.
## Primary Indications
* Acute bacterial rhinosinusitis
* Community-acquired pneumonia
* Lower respiratory tract infections
* Acute otitis media (AOM)
* Skin and skin structure infections
* Urinary tract infections (UTIs)
* Bite wounds (animal or human)
## Adult Dosing
Standard dosing is based on the amoxicillin component:
* **Mild to Moderate Infections:** 500 mg (amoxicillin) every 12 hours or 250 mg every 8 hours.
* **Severe Infections/Respiratory Infections:** 875 mg (amoxicillin) every 12 hours or 500 mg every 8 hours.
* **Max Daily Dose:** Dose is limited by the clavulanate component to prevent GI distress and potential hepatotoxicity; usually not exceeding 1750–2500 mg amoxicillin per day depending on the formulation.
## Pediatric Dosing
* **General Dosing:** 20 to 45 mg/kg/day (based on amoxicillin component) divided every 8–12 hours.
* **AOM (Recurrent or Resistant):** 90 mg/kg/day divided every 12 hours (using the 600 mg/5 mL suspension to minimize clavulanate dosing).
* **Maximum:** Do not exceed adult maximum daily doses.
## Dose Adjustments
* **Renal Impairment:** Adjustments required for 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; monitor liver function due to the risk of cholestatic jaundice associated with the clavulanate component.
## Contraindications
* History of serious hypersensitivity (anaphylaxis) to any penicillin or cephalosporin.
* History of cholestatic jaundice or hepatic dysfunction associated with previous use of amoxicillin-clavulanate.
## Adverse Effects
* **Common:** Diarrhea (frequently associated with clavulanate), nausea, vomiting, rash.
* **Serious:** Clostridioides difficile-associated diarrhea (CDAD), severe cutaneous adverse reactions (SCAR), cholestatic jaundice, and anaphylaxis.
## Key Drug Interactions
* **Methotrexate:** Penicillins may decrease the renal excretion of methotrexate, increasing the risk of toxicity.
* **Warfarin:** May increase INR/bleeding risk due to alteration of gut flora (vitamin K synthesis).
* **Oral Contraceptives:** May reduce efficacy; consider back-up contraception during therapy.
## Monitoring
* Monitor for signs of anaphylaxis during the first dose.
* Periodic assessment of renal and hepatic function during prolonged therapy.
* Monitor for signs of superinfection or *C. difficile* (persistent watery diarrhea).
## Clinical Pearls
* **Take with food** to minimize gastrointestinal upset.
* The ratio of amoxicillin to clavulanate varies by tablet strength; 875 mg tablets and 500 mg tablets are not bioequivalent and cannot be substituted simply by doubling the dose.
* Avoid using the 250 mg or 500 mg tablets in patients needing 90 mg/kg/day for AOM, as the excessive clavulanate component will cause significant diarrhea.
* In patients with suspected mononucleosis, avoid amoxicillin-clavulanate due to high risk of non-allergic maculopapular rash.
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**Educational Disclaimer:** This information is for educational purposes only. Clinical guidelines and local resistance patterns change frequently. Always consult the most current institutional formulary, prescribing information (package insert), or a clinical pharmacist before prescribing or administering medication.
