What is the recommended antibiotic dosing for uncomplicated urinary tract infections (UTIs)?

Recommended Antibiotic Dosing for Uncomplicated Urinary Tract Infections (UTIs)

For uncomplicated bacterial cystitis in women, prescribe nitrofurantoin for 5 days, trimethoprim-sulfamethoxazole (TMP-SMX) for 3 days, or fosfomycin as a single dose. For uncomplicated pyelonephritis, prescribe fluoroquinolones for 5-7 days or TMP-SMX for 14 days based on antibiotic susceptibility. 1

First-Line Treatment Options for Uncomplicated Cystitis

Women with Uncomplicated Cystitis

• Nitrofurantoin: 100 mg orally twice daily for 5 days 1
• TMP-SMX: One double-strength tablet (160/800 mg) orally twice daily for 3 days 1, 2
• Fosfomycin: 3 g single oral dose 1

Important Considerations

• Escherichia coli accounts for >75% of all bacterial cystitis cases, so empirical antibiotics should target this organism 1
• Fluoroquinolones should not be used as first-line empiric therapy despite high efficacy in 3-day regimens due to:
  • High propensity for adverse effects 1
  • Increasing resistance rates 3
  • Should be reserved for patients with history of resistant organisms 1

Treatment for Uncomplicated Pyelonephritis

Oral Therapy Options

• Fluoroquinolones:
  • Ciprofloxacin: 500 mg twice daily for 7 days 1
  • Levofloxacin: 750 mg once daily for 5 days 1
• TMP-SMX: One double-strength tablet (160/800 mg) twice daily for 14 days (when susceptibility is known) 1, 2

Parenteral Therapy Options (if hospitalization required)

• Ciprofloxacin: 400 mg IV twice daily 1
• Levofloxacin: 750 mg IV once daily 1
• Ceftriaxone: 1-2 g IV once daily 1
• Gentamicin: 5 mg/kg IV once daily 1

Special Considerations

Antibiotic Resistance

• Local resistance patterns should guide empiric therapy choices 1, 3
• TMP-SMX should not be used empirically for pyelonephritis without culture and susceptibility testing due to high resistance rates 1
• Recent studies show 5-day courses of fluoroquinolones are noninferior to 10-day courses for pyelonephritis, with clinical cure rates >93% 1

Catheter-Associated UTIs

• For catheter-associated UTIs with prompt symptom resolution: 7-day treatment course 1
• For catheter-associated UTIs with delayed response: 10-14 day treatment course 1
• Levofloxacin 750 mg daily for 5 days may be considered for non-severe catheter-associated UTIs 1
• A 3-day regimen may be appropriate for women ≥65 years who develop catheter-associated UTI without upper tract symptoms after catheter removal 1

Multidrug-Resistant Organisms

• For uncomplicated UTIs due to vancomycin-resistant enterococci (VRE):
  • Fosfomycin: 3 g single oral dose 1
  • Nitrofurantoin: 100 mg orally every 6 hours 1
• For simple cystitis due to carbapenem-resistant Enterobacteriaceae (CRE):
  • Single-dose aminoglycoside therapy 1

Common Pitfalls to Avoid

• Treating asymptomatic bacteriuria - this should be avoided as it contributes to antibiotic resistance without clinical benefit 1
• Using fluoroquinolones as first-line empiric therapy for uncomplicated cystitis despite their efficacy due to adverse effects and resistance concerns 1, 3
• Prescribing longer antibiotic courses than necessary, which increases risk of adverse effects without improving outcomes 1, 4
• Failure to adjust therapy based on culture results and clinical response 1
• Not considering local resistance patterns when selecting empiric therapy 1, 3

Treatment Duration Summary

• Uncomplicated cystitis in women:
  • Nitrofurantoin: 5 days 1
  • TMP-SMX: 3 days 1
  • Fosfomycin: single dose 1
• Uncomplicated pyelonephritis:
  • Fluoroquinolones: 5-7 days 1
  • TMP-SMX: 14 days 1
• Catheter-associated UTI:
  • Standard: 7 days (prompt response) or 10-14 days (delayed response) 1
  • Levofloxacin: 5 days for non-severe cases 1