Augmentin (Amoxicillin-Clavulanate) for Urinary Tract Infections
For uncomplicated UTIs in adults, Augmentin 500/125 mg twice daily for 3 days is an appropriate regimen, though it demonstrates lower cure rates (58-83%) compared to fluoroquinolones and should be reserved for situations where first-line agents cannot be used. 1
Dosing Regimens by Clinical Scenario
Uncomplicated Cystitis in Adults
- Standard dose: Amoxicillin-clavulanate 500/125 mg orally twice daily for 3 days 1
- Alternative dose: 375 mg orally three times daily for 6-7 days 2, 3
- Clinical cure rates range from 67-84%, which is significantly lower than trimethoprim-sulfamethoxazole (89%) or ciprofloxacin (77-96%) 1, 4
Febrile UTIs in Children (2-24 months)
- Dose: 20-40 mg/kg per day divided into 3 doses 1
- Duration: 7-14 days 1
- Use only if local susceptibility patterns support its use and adjust based on culture results 1
Recurrent UTIs
- Dose: 250/125 mg (one tablet) every 8 hours for 7 days 3
- Microbiological cure rates: 84% at 1 week post-treatment, declining to 67% at 1 month 3
Complicated UTIs and Pyelonephritis
- Dose: 375 mg three times daily for 7-12 days 2
- In patients with mild chronic renal insufficiency (GFR 55-70 mL/min), this regimen achieved normalization of clinical and laboratory indices in 68-86% of cases depending on the clinical scenario 2
Important Clinical Considerations
Efficacy Limitations
- Augmentin shows significantly lower cure rates than co-trimoxazole for uncomplicated UTIs (83% vs 100%, p=0.039) 4
- When compared to ciprofloxacin for 3-day treatment, amoxicillin-clavulanate achieved only 58% clinical cure at 4 months versus 77% with ciprofloxacin (p<0.001) 1
- Even among organisms susceptible to the drug, cure rates were only 60% versus 77% with fluoroquinolones 1
Resistance Patterns
- Approximately 12-25% of urinary pathogens may be resistant to amoxicillin, with some showing resistance even to the amoxicillin-clavulanate combination 4
- Success rates for amoxicillin-resistant organisms treated with Augmentin are approximately 70% 5
- Critical caveat: Always check local antibiotic susceptibility patterns before empiric use 1
Adverse Effects
- Gastrointestinal side effects occur in approximately 20% of patients but are generally mild 3
- Severe diarrhea and abdominal pain can occur in a small percentage (approximately 8%) of patients 4
- Treatment discontinuation due to side effects is rare 3
When to Use Augmentin
Augmentin should be considered when:
- First-line agents (trimethoprim-sulfamethoxazole, nitrofurantoin, fosfomycin) cannot be used due to allergy or resistance 1
- Culture results confirm susceptibility to amoxicillin-clavulanate 1
- Treating amoxicillin-resistant organisms in settings where other options are limited 5, 6
When NOT to Use Augmentin
- Do not use for febrile UTIs or pyelonephritis when fluoroquinolone resistance is <10% in your community—fluoroquinolones are superior 1
- Avoid as empiric first-line therapy for uncomplicated cystitis given lower efficacy compared to standard agents 1
- Not appropriate for multidrug-resistant organisms (CRE, VRE, CRAB) where specialized regimens are required 1