First-Line Treatment for Uncomplicated UTI
For uncomplicated urinary tract infections in women, use nitrofurantoin 100 mg twice daily for 5 days as the preferred first-line agent, with trimethoprim-sulfamethoxazole (160/800 mg twice daily for 3 days) or fosfomycin (3 g single dose) as alternatives depending on local resistance patterns. 1, 2, 3
Primary Treatment Options
The choice of first-line antibiotic should be guided by local resistance patterns and the principle of minimizing "collateral damage" to normal flora 1:
Nitrofurantoin 100 mg twice daily for 5 days is the preferred first-line agent due to lower treatment failure rates compared to TMP-SMX and minimal impact on antimicrobial resistance 2, 3
Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg twice daily for 3 days should only be used if local E. coli resistance rates are below 20% 1, 2, 3, 4
Fosfomycin trometamol 3 g as a single dose offers convenient single-dose therapy, though it may have slightly inferior efficacy compared to standard regimens 1, 2, 5
Treatment Duration
Keep antibiotic courses as short as reasonable, generally no longer than 7 days 1:
Agents to Avoid as First-Line
Fluoroquinolones (ciprofloxacin, levofloxacin) should be reserved as alternative agents, not first-line, due to significant collateral damage, promotion of resistance, and FDA warnings about serious adverse effects affecting tendons, muscles, joints, nerves, and the central nervous system 2, 3, 6
Beta-lactams (amoxicillin, ampicillin) should not be used for empiric treatment due to inferior efficacy and high resistance prevalence 3, 7
When to Obtain Urine Culture Before Treatment
Urine culture and susceptibility testing should be obtained in these specific situations 1, 3, 8:
- Recurrent UTIs
- Treatment failure or symptoms persisting/recurring within 2-4 weeks
- History of resistant organisms
- Atypical presentation
- All men with UTI symptoms
- Adults ≥65 years old
Diagnostic Approach in Women
A self-diagnosis of UTI with typical symptoms (frequency, urgency, dysuria, nocturia, suprapubic pain) without vaginal discharge is accurate enough to diagnose uncomplicated UTI without office visit or urine culture 8, 7
Special Considerations
Asymptomatic bacteriuria should NOT be treated except in pregnant women or patients scheduled for invasive urinary tract procedures 1, 3
Surveillance urine testing should be omitted in asymptomatic patients with recurrent UTIs 1, 3
Patient-initiated self-start treatment may be offered to select patients with recurrent UTIs while awaiting culture results 3
Nitrofurantoin safety: The extremely low risk of serious pulmonary (0.001%) or hepatic toxicity (0.0003%) should not deter short-term use 1, 2
Treatment in Men
Men with lower UTI symptoms should always receive antibiotics with urine culture guiding antibiotic choice 8:
- First-line antibiotics: trimethoprim, TMP-SMX, or nitrofurantoin for 7 days (longer than women) 8
- Consider possibility of urethritis and prostatitis in men with UTI symptoms 8
Important Contraindications
- Nitrofurantoin is contraindicated for pyelonephritis as it does not achieve adequate tissue concentrations 2, 5
- If fever, flank pain, or systemic symptoms suggest pyelonephritis, choose a fluoroquinolone or other agent with good tissue penetration 2
- Avoid nitrofurantoin if creatinine clearance is <60 mL/min 2