Nitrofurantoin Dosing for Uncomplicated UTI

For uncomplicated UTIs in women, use nitrofurantoin monohydrate/macrocrystals 100 mg twice daily for 5 days as first-line therapy. 1

Standard Dosing for Women with Uncomplicated Cystitis

The recommended regimen is nitrofurantoin monohydrate/macrocrystals 100 mg orally twice daily for 5-7 days, with 5 days being the preferred duration per IDSA and European guidelines 1
This 5-day regimen achieves clinical cure rates of 88-93% and bacterial cure rates of 81-92% 1
The 5-day course is equivalent in efficacy to trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days 1

Nitrofurantoin macrocrystals can be dosed at 50-100 mg four times daily for 5 days, though this is less convenient than twice-daily dosing 1
For vancomycin-resistant enterococcal (VRE) UTIs specifically, use 100 mg four times daily 1, 2

For men, use nitrofurantoin 100 mg orally every 6 hours (four times daily) for 7-14 days 3
The 14-day duration is recommended when prostatitis cannot be excluded 3
Important caveat: Nitrofurantoin has substantially lower efficacy in males, with a 25% failure rate compared to 10-16% in females, so consider alternative agents as first-line in men 3

Nitrofurantoin is absolutely contraindicated when creatinine clearance is <60 mL/min due to inadequate urinary drug concentrations and increased risk of peripheral neuropathy 3, 2
Do not use if early pyelonephritis is suspected, as nitrofurantoin does not achieve adequate tissue concentrations 1, 3
Avoid in patients with perinephric abscess 1

Nausea and headache are the most frequent side effects, occurring in 5.6-34% of patients 1
Gastrointestinal symptoms are mild, reversible, and predominantly self-limited 4
Serious hypersensitivity reactions (pulmonary fibrosis, hepatotoxicity) are rare with short-term use 4

Children ≥12 years: 100 mg twice daily for 7 days 1
Children <12 years: 5-7 mg/kg/day divided into 4 doses (maximum 100 mg/dose) for 7 days or at least 3 days after obtaining sterile urine 1

For VRE uncomplicated UTIs, use 100 mg four times daily for 7-10 days until clinical resolution 2
Alternative options include fosfomycin 3 g single dose or high-dose ampicillin 2

Routine post-treatment urinalysis or urine cultures are NOT indicated for asymptomatic patients 1
Perform urine culture with susceptibility testing only if symptoms do not resolve by end of treatment or recur within 2 weeks 1
If symptoms persist or recur, retreat with a 7-day regimen using an alternative agent 1

Do not use 3-day regimens - clinical efficacy drops to only 61-70% with 3-day courses 4
Do not adjust dose for renal impairment - instead, choose an alternative agent entirely when CrCl <60 mL/min 3, 2
Do not use as monotherapy in males without considering the high failure rate - fluoroquinolones or trimethoprim-sulfamethoxazole may be more appropriate first-line options 3
Do not extend treatment beyond 7 days in women unless symptoms persist, as shorter courses minimize adverse effects while maintaining efficacy 1

Nitrofurantoin has similar clinical cure rates to ciprofloxacin and trimethoprim-sulfamethoxazole when comparing 7-day regimens 1
Meta-analyses show slight advantage to comparator drugs in microbiological efficacy (risk ratio 0.93), though clinical outcomes remain equivalent 4
Nitrofurantoin remains first-line due to minimal resistance development and limited collateral damage to normal flora 1