Recommended Dosage of Augmentin for Urinary Tract Infections
For uncomplicated UTIs, Augmentin (amoxicillin-clavulanate) should be dosed at 500/125 mg orally every 8 hours for 5-7 days, or 875/125 mg orally every 12 hours for 5-7 days. 1
Dosing Recommendations Based on UTI Type
Uncomplicated UTIs
- First-line option: 500/125 mg orally every 8 hours for 5-7 days
- Alternative option: 875/125 mg orally every 12 hours for 5-7 days
Complicated UTIs
- Standard dosing: 875/125 mg orally every 12 hours for 10-14 days 1
- Alternative: 500/125 mg orally every 8 hours for 10-14 days 1
Pyelonephritis
- Oral therapy: 875/125 mg orally every 12 hours for 14 days 2
- Initial parenteral therapy may be needed for severe cases before transitioning to oral therapy
Clinical Evidence Supporting These Recommendations
The FDA label for Augmentin provides strong evidence for these dosing regimens based on clinical trials involving 1,191 patients with either lower respiratory tract infections or complicated UTIs. The trials demonstrated comparable efficacy between the 875/125 mg every 12 hours and 500/125 mg every 8 hours dosing regimens 1.
Importantly, the 875/125 mg every 12 hours regimen was associated with a statistically significant lower rate of severe diarrhea (1% vs 2%) compared to the 500/125 mg every 8 hours regimen 1.
Special Considerations
Renal Impairment
- Creatinine clearance >30 mL/min: No dosage adjustment needed
- Creatinine clearance 10-30 mL/min: 500/125 mg every 12 hours
- Creatinine clearance <10 mL/min: 500/125 mg every 24 hours
Duration of Therapy
- Uncomplicated UTIs: 5-7 days is typically sufficient 2
- Complicated UTIs: 10-14 days is recommended 2, 1
- Severe pyelonephritis: May require 14 days of therapy 2
Clinical Efficacy
Clinical trials have demonstrated bacteriological success rates of:
- 81% at 2-4 days post-therapy
- 52-58% at 5-9 days post-therapy
- 52-55% at 2-4 weeks post-therapy 1
Earlier studies showed microbiological cure rates of 84% one week after treatment and 67% one month later in patients with recurrent UTIs treated with 250/125 mg every 8 hours for 7 days 3.
Potential Pitfalls and Caveats
- Gastrointestinal side effects: Diarrhea is the most common adverse effect (14-15% of patients) 1
- Resistance concerns: Consider local resistance patterns before prescribing
- Drug interactions: Monitor patients on anticoagulants as Augmentin may increase INR
- Allergic reactions: Contraindicated in patients with known hypersensitivity to penicillins
Alternative Options When Augmentin Cannot Be Used
For patients who cannot take Augmentin, the European Association of Urology recommends:
- Fluoroquinolones (if local resistance <10%)
- Trimethoprim-sulfamethoxazole (160/800 mg twice daily for 14 days)
- Cephalosporins (e.g., cefpodoxime 200 mg twice daily for 10 days) 4
Remember that Augmentin is not considered first-line therapy for uncomplicated cystitis according to current guidelines, but it remains a valuable option for complicated UTIs or when first-line agents cannot be used due to resistance or contraindications.