Treatment of Uncomplicated Bacterial Cystitis
For women with uncomplicated bacterial cystitis, prescribe nitrofurantoin 100 mg twice daily for 5 days as first-line therapy, or alternatively trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days if local E. coli resistance is below 20%, or fosfomycin 3 g as a single dose. 1
First-Line Antibiotic Options
The choice among first-line agents depends on local resistance patterns, drug availability, and patient-specific factors:
Nitrofurantoin (Preferred)
- Dose: 100 mg twice daily for 5 days 1
- Advantages: Minimal collateral damage to gut flora, low resistance rates, and proven equivalence to trimethoprim-sulfamethoxazole 2
- Evidence: A randomized trial of 338 women demonstrated 84% clinical cure at 30 days with 5-day nitrofurantoin versus 79% with 3-day trimethoprim-sulfamethoxazole 2
Trimethoprim-Sulfamethoxazole
- Dose: 160/800 mg (one double-strength tablet) twice daily for 3 days 1
- Critical caveat: Only use when local E. coli resistance is documented to be <20% 1
- Resistance concern: Rising resistance rates have demoted this from automatic first-line status, particularly outside the United States 1
- Clinical failure: In one study, only 41% of women infected with trimethoprim-sulfamethoxazole-resistant organisms achieved clinical cure versus 84% with susceptible isolates 2
Fosfomycin Trometamol
- Dose: 3 g as a single oral dose 1
- Advantages: Single-dose convenience, minimal resistance, minimal collateral damage 1
- Limitation: FDA data suggest inferior efficacy compared to standard short-course regimens 1
Second-Line Options (When First-Line Cannot Be Used)
Fluoroquinolones (Reserve for Resistant Cases)
- Agents: Ciprofloxacin, levofloxacin, ofloxacin, norfloxacin 1
- Duration: 3 days 1
- Strong recommendation: Reserve fluoroquinolones for important uses other than acute cystitis due to high propensity for collateral damage and promotion of resistance 1
- Only use when: Recommended agents cannot be used due to allergy or documented resistance 1
Beta-Lactam Antibiotics (Use with Caution)
- Agents: Amoxicillin-clavulanate, cefdinir, cefaclor, cefpodoxime-proxetil 1
- Duration: 3-7 days 1
- Cephalexin: 500 mg every 12 hours for 7-14 days for uncomplicated cystitis 3
- Limitations: Generally inferior efficacy and more adverse effects compared to other UTI antimicrobials 1
- Use only when: Other recommended agents cannot be used 1
Agents to Avoid
- Never use amoxicillin or ampicillin empirically due to poor efficacy and very high worldwide resistance rates 1
Special Populations
Men with Uncomplicated Cystitis
- Same antibiotic choices as women, though true "uncomplicated" cystitis is rare in men 1
- Consider longer treatment courses given anatomic differences 1
Pregnant Women
- Avoid nitrofurantoin near term and trimethoprim in first trimester 1
- Beta-lactams are generally safe options 1
When to Obtain Urine Culture
Do not routinely obtain urine cultures for typical uncomplicated cystitis. 1 Obtain cultures only in these situations:
- Suspected pyelonephritis 1
- Symptoms not resolving or recurring within 2-4 weeks after treatment 1
- Atypical symptoms 1
- Pregnancy 1
Follow-Up and Treatment Failure
- No routine post-treatment testing needed for asymptomatic patients 1
- If symptoms persist or recur within 2 weeks: Obtain urine culture with susceptibility testing and retreat with a different agent for 7 days, assuming resistance to the initial agent 1
Common Pitfalls to Avoid
- Do not prescribe fluoroquinolones as first-line therapy despite their high efficacy—reserve them for resistant infections to preserve their utility 1
- Do not assume trimethoprim-sulfamethoxazole will work without knowing local resistance patterns—resistance >20% predicts clinical failure 1, 2
- Do not extend treatment duration beyond recommended courses without clinical indication—longer courses increase adverse events without improving outcomes 1
- Do not use beta-lactams as first-line agents unless other options are contraindicated—they have inferior efficacy 1