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# Mega CV (Amoxicillin/Potassium Clavulanate)
## Overview
Mega CV is a combination antibiotic consisting of amoxicillin (a beta-lactam penicillin) and potassium clavulanate (a beta-lactamase inhibitor). The addition of clavulanate expands the spectrum of amoxicillin to include beta-lactamase-producing organisms.
## Primary Indications
Treatment of infections caused by susceptible organisms, including community-acquired pneumonia, otitis media, sinusitis, skin and skin structure infections, and urinary tract infections.
## Adult Dosing
* **Standard dose:** 500 mg/125 mg orally every 8 or 12 hours.
* **Severe infection/Respiratory tract infection:** 875 mg/125 mg orally every 12 hours.
* **Maximum daily dose:** Should not exceed 1750 mg of amoxicillin per day for the 875 mg formulation to avoid gastrointestinal toxicity attributed to high clavulanate exposure.
## Pediatric Dosing
* **Standard dose:** 20 to 45 mg/kg/day (based on amoxicillin component) divided every 8 to 12 hours, depending on the severity and type of infection.
* **Recurrent/Resistant Otitis Media:** High-dose regimen of 80–90 mg/kg/day (amoxicillin component) divided every 12 hours.
* *Note:* Use the 7:1 ratio (e.g., 600 mg/42.9 mg/5 mL suspension) for high-dose regimens to prevent excessive clavulanate intake.
## Dose Adjustments
* **Renal Impairment:** Required. If CrCl < 30 mL/min, avoid the 875 mg tablet. Dosing intervals must be extended or doses reduced based on specific creatinine clearance levels.
* **Hepatic Impairment:** Use with caution; monitor hepatic function periodically.
## Contraindications
* History of serious hypersensitivity (anaphylaxis) to any penicillin.
* History of cholestatic jaundice or hepatic dysfunction associated with previous amoxicillin/clavulanate use.
## Adverse Effects
* **Common:** Diarrhea, nausea, vomiting, abdominal pain, and skin rash.
* **Serious:** Pseudomembranous colitis (*C. difficile*-associated diarrhea), hepatotoxicity (usually cholestatic jaundice), and severe hypersensitivity reactions (Stevens-Johnson syndrome, angioedema).
## Key Drug Interactions
* **Warfarin:** May increase INR and bleeding risk; monitor coagulation parameters.
* **Methotrexate:** Amoxicillin may decrease renal elimination, leading to increased methotrexate toxicity.
* **Probenecid:** Decreases renal excretion of amoxicillin, increasing serum levels.
* **Oral Contraceptives:** Potential for reduced efficacy (though evidence is debated, backup contraception is often recommended during treatment).
## Monitoring
* Renal and hepatic function (especially during prolonged therapy).
* Signs of hypersensitivity or severe cutaneous adverse reactions.
* Monitor for watery or bloody stools (potential *C. difficile* infection).
## Clinical Pearls
* **Administration:** Take with food to minimize gastrointestinal upset.
* **Clavulanate Limit:** The 875 mg tablet contains 125 mg of clavulanate. Do not use two 500 mg tablets to reach an 875 mg dose, as this doubles the clavulanate amount, increasing the risk of adverse GI effects.
* **Stability:** Once reconstituted, oral suspensions usually require refrigeration and expire within 10 days.
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**Educational Disclaimer:** This information is for educational purposes only. Dosing, contraindications, and drug interactions can change. Always verify current prescribing information using local hospital formularies, the manufacturer’s package insert, or reputable clinical databases (e.g., Lexicomp, UpToDate) before prescribing or administering medication.
