What are the indications, recommended dosing, contraindications, and common adverse effects of faropenem for treating uncomplicated community‑acquired infections in adults and children?

Faropenem: Clinical Overview

Faropenem is an oral carbapenem antibiotic with demonstrated efficacy against common respiratory and urinary pathogens, but it is not FDA-approved in the United States and does not appear in current major infectious disease guidelines for intra-abdominal or community-acquired infections.

Indications

Faropenem has been studied and approved in some countries (notably Japan and parts of Asia) for:

• Respiratory tract infections including acute bacterial sinusitis, community-acquired pneumonia, and acute exacerbations of chronic bronchitis 12
• Uncomplicated urinary tract infections (acute cystitis), where it shows activity against fluoroquinolone-resistant and ESBL-producing E. coli 3
• Uncomplicated skin and skin structure infections 1
• Pediatric infections including upper respiratory tract infections, urinary tract infections, dermatological infections, and otitis media 4

Important caveat: Faropenem received a non-approvable letter from the FDA in 2006, and development in the United States has stalled 2. It is not listed among recommended agents in current IDSA/SIS guidelines for intra-abdominal infections 555 or other major U.S. treatment guidelines.

Antimicrobial Spectrum

• Gram-positive coverage: Good activity against common respiratory streptococci and many aerobic gram-positive organisms 1
• Gram-negative coverage: Excellent activity against E. coli and Klebsiella spp. with CTX-M and non-CTX-M ESBLs, with modal MICs of 0.5–1 mg/L and >95% susceptibility at ≤2 mg/L 6
• ESBL producers: Faropenem demonstrates stability against β-lactamases, including many ESBL-producing Enterobacteriaceae 63
• AmpC-producing organisms: Less reliable activity; modal MICs for AmpC-derepressed Enterobacter and Citrobacter spp. are 2–4 mg/L, with approximately 5% requiring MICs of 16 mg/L 6
• Anaerobic coverage: Good activity against anaerobes 1
• Carbapenemase producers: Substantially reduced activity against NMC-A (Class A) and IMP (Class B) carbapenemase-producing strains 6

Recommended Dosing

Adults

• Standard dose: 600 mg orally twice daily 2
• Acute uncomplicated cystitis: 200 mg three times daily for 7 days (superior microbiological eradication compared to 3-day regimen: 66.7% vs 58.9%, P=0.048) 3

Pediatric Patients

• Standard dose: 15 mg/kg/day divided into three doses 4
• Available as oral dry syrup formulation for children 4
• Phase II data support dosing range of 7.5–40 mg/kg for acute otitis media 2

Contraindications and Precautions

• β-lactam allergy: As a carbapenem, faropenem is contraindicated in patients with documented severe hypersensitivity to β-lactam antibiotics 4
• Renal impairment: Specific dose adjustments are not well-established in published literature; caution is advised
• Resistance concerns: Broad carbapenem use may promote carbapenem resistance; reserve for appropriate indications 7

Common Adverse Effects

• Gastrointestinal: Diarrhea is the most common adverse event, reported in approximately 9.5% of patients 3
• Other GI effects: Nausea and vomiting 1
• Overall tolerability: Adverse events appear minimal with a favorable safety profile 41

Clinical Efficacy Data

• Non-inferiority demonstrated versus azithromycin and clarithromycin for acute exacerbations of chronic bronchitis 2
• Non-inferiority demonstrated versus comparators for acute bacterial sinusitis, community-acquired pneumonia, and uncomplicated skin/skin structure infections 1
• Clinical efficacy in acute uncomplicated cystitis: 76.7% (3-day) and 80.2% (7-day regimen) 3

Critical Limitations

• Not FDA-approved: Development halted in the U.S. after 2006 non-approvable letter; four additional phase III trials would be required for approval 2
• Not guideline-recommended: Absent from IDSA/SIS guidelines for intra-abdominal infections 5557, which recommend ertapenem, meropenem, imipenem-cilastatin, or doripenem as carbapenem options
• Limited global availability: Primarily available in Japan and select Asian markets 4
• Urinary tract concentration data lacking: Clinical utility for UTIs depends on adequate urinary levels, which require further study 6

Place in Therapy

Faropenem may serve as an oral carbapenem option in regions where it is approved, particularly for outpatient treatment of community-acquired infections caused by ESBL-producing organisms when oral alternatives are limited. However, clinicians in the United States and most Western countries should rely on guideline-recommended agents such as oral amoxicillin-clavulanate for step-down therapy 7 or parenteral carbapenems (ertapenem, meropenem, imipenem-cilastatin, doripenem) for severe infections 555.