Nitrofurantoin Duration for Uncomplicated UTI
For an uncomplicated UTI sensitive to nitrofurantoin, prescribe nitrofurantoin 100 mg twice daily for 5 days. 1, 2
Recommended Treatment Regimen
- Nitrofurantoin 100 mg twice daily for 5 days is the standard first-line duration that balances efficacy with minimizing adverse effects 1, 2, 3
- This 5-day course achieves clinical cure rates of 79-92% for common uropathogens 3
- The AUA/CUA/SUFU guidelines emphasize treating acute cystitis with "as short a duration of antibiotics as reasonable, generally no longer than seven days" 1
Why Not Shorter or Longer?
- Do not use 3-day courses of nitrofurantoin—clinical efficacy drops significantly to only 61-70% with this shorter duration 3
- Avoid extending beyond 5-7 days unless there are complicating factors, as longer courses increase adverse effects without improving outcomes 1
- Meta-analyses confirm that 5-7 day nitrofurantoin regimens are equivalent to comparator antibiotics (trimethoprim-sulfamethoxazole, ciprofloxacin) for clinical cure 3
Important Caveats
- This recommendation applies only to uncomplicated lower UTI (cystitis) in non-pregnant women 1, 2
- Do not use nitrofurantoin for pyelonephritis or upper tract infections—it does not achieve adequate tissue concentrations in the renal parenchyma 2
- Avoid in infants under 4 months due to hemolytic anemia risk 2
- Men typically require longer treatment durations and alternative agents may be preferred 2
Alternative First-Line Options (if nitrofurantoin unavailable)
- Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days (only if local resistance <20%) 1, 2
- Fosfomycin 3 g as a single dose 1, 2