Can Augmentin (amoxicillin-clavulanate) be used to treat a urinary tract infection (UTI)?

Amoxicillin-Clavulanate for UTI Treatment

Amoxicillin-clavulanate (Augmentin) should NOT be used as first-line therapy for uncomplicated urinary tract infections due to inferior efficacy, higher adverse effect rates, and concerns about antimicrobial resistance compared to recommended first-line agents.

Recommended Treatment Hierarchy for UTIs

First-Line Options (Preferred)

• Nitrofurantoin (100mg twice daily for 5-7 days)
• Trimethoprim-sulfamethoxazole (if local resistance <20%)
• Fosfomycin (3g single dose)

Second-Line Options

• Fluoroquinolones (only when first-line options cannot be used)

Third-Line Options (When Other Options Cannot Be Used)

• β-lactams including amoxicillin-clavulanate (7 days)

Evidence Against Amoxicillin-Clavulanate as First-Line

The 2011 Infectious Diseases Society of America (IDSA) and European Society for Microbiology and Infectious Diseases guidelines explicitly state that β-lactam agents, including amoxicillin-clavulanate, should only be used "when other recommended agents cannot be used" 1. These guidelines note that:

1. β-lactams "generally have inferior efficacy and more adverse effects compared with other UTI antimicrobials" 1
2. β-lactams "should be used with caution for uncomplicated cystitis" 1
3. β-lactams have a "propensity to promote more rapid recurrence of UTI" 1

When Amoxicillin-Clavulanate May Be Appropriate

Despite not being first-line, amoxicillin-clavulanate does have FDA approval for complicated UTIs 2. Clinical studies have demonstrated efficacy in:

• Complicated UTIs with abnormalities of the urinary tract 2
• UTIs caused by β-lactamase-producing organisms resistant to amoxicillin alone 3
• Recurrent UTIs with an 84% microbiological cure rate one week after treatment 4

Dosing Recommendations When Used

When amoxicillin-clavulanate must be used for UTIs, the FDA-approved dosing is:

• 875mg/125mg every 12 hours OR
• 500mg/125mg every 8 hours

Both dosing regimens showed comparable efficacy in clinical trials, but the twice-daily regimen had a lower rate of severe diarrhea (1% vs 2%) 2.

Concerns with Amoxicillin-Clavulanate Use

Antimicrobial Stewardship

Antibiotic stewardship for UTIs starts with treating according to clinical practice guidelines using short-duration nitrofurantoin, TMP-SMX, or fosfomycin as first-line therapy 1. Using broader spectrum agents like amoxicillin-clavulanate can lead to:

1. Loss of protective periurethral and vaginal microbiota, potentially causing more recurrences 1
2. Increased risk of Clostridium difficile infection 1
3. Higher rates of adverse effects, particularly diarrhea (14-15% of patients) 2

Resistance Concerns

In some regions, there is high resistance to amoxicillin-clavulanate. A study from Ireland showed 54.5% persistent resistance to amoxicillin-clavulanate in E. coli UTIs 1.

Special Populations

Pediatric Patients

For pediatric UTIs, amoxicillin-clavulanate may be considered among the first-line options along with trimethoprim-sulfamethoxazole or third-generation cephalosporins, based on local resistance patterns 5.

Complicated UTIs

For complicated UTIs or pyelonephritis, parenteral antibiotics are often preferred initially, with oral options including fluoroquinolones when resistance rates are low (<10%) 1.

Conclusion

While amoxicillin-clavulanate can be effective for UTIs and has FDA approval for this indication, current guidelines recommend reserving it as a third-line option due to concerns about efficacy, side effects, and antimicrobial stewardship. First-line treatments with better efficacy and fewer side effects should be prioritized whenever possible.