What is the first-line treatment for bacterial cystitis?

First-Line Treatment for Bacterial Cystitis

The first-line treatments for uncomplicated bacterial cystitis include nitrofurantoin (100 mg twice daily for 5 days), trimethoprim-sulfamethoxazole (one double-strength tablet every 12 hours for 3 days if local resistance is <20%), and fosfomycin (single 3g dose). 1

Treatment Algorithm

1. First-line options (in order of preference):

   • Trimethoprim-sulfamethoxazole (TMP-SMX): One double-strength tablet (160/800 mg) every 12 hours for 3 days

     • Use only when local E. coli resistance is <20%
     • High efficacy: 90-100% clinical cure rates and 85-100% bacterial eradication rates 1
     • FDA-approved for urinary tract infections caused by susceptible strains of E. coli, Klebsiella, Enterobacter, M. morganii, P. mirabilis, and P. vulgaris 2

   • Nitrofurantoin: 100 mg twice daily for 5 days

     • Excellent option when TMP-SMX cannot be used
     • First-line alternative for patients with TMP-SMX allergy 1

   • Fosfomycin: Single 3g dose

     • Convenient single-dose administration
     • Lower efficacy than multi-day regimens but offers convenience 1

2. Second-line options:

   • Fluoroquinolones: 250 mg twice daily for 3 days
     • Reserved for situations where first-line options cannot be used
     • Concerns about "collateral damage" (ecological adverse effects)
     • High resistance rates (approximately 24% for E. coli) 1

Special Considerations

Patient-Specific Factors

• Renal impairment: Avoid nitrofurantoin if GFR <30 ml/min 1
• Pregnancy: Nitrofurantoin 100 mg twice daily for 5-7 days is recommended (avoid in third trimester) 1
• Diabetes: Requires special attention due to higher risk of complications; ensure good glycemic control during treatment 1

Local Resistance Patterns

• TMP-SMX should only be used empirically when local E. coli resistance is <20% 1, 3
• Knowledge of local susceptibility patterns is essential for appropriate empiric therapy 4

Common Pitfalls to Avoid

1. Inappropriate duration of therapy:

   • Most prescriptions for TMP-SMX, nitrofurantoin, and fluoroquinolones are longer than guideline recommendations (73-82% of prescriptions) 5
   • Adhere to recommended durations: 3 days for TMP-SMX, 5 days for nitrofurantoin, single dose for fosfomycin 1

2. Overuse of fluoroquinolones:

   • Despite being second-line agents, fluoroquinolones remain the most commonly prescribed antibiotics for uncomplicated cystitis (51.6% in some studies) 5
   • Reserve fluoroquinolones for situations where first-line options cannot be used 1

3. Failure to consider antibiotic stewardship:

   • Use the narrowest spectrum agent likely to be effective 1
   • Consider local resistance patterns when selecting empiric therapy 4

Follow-up

• Evaluate clinical response within 48-72 hours of initiating therapy
• No routine follow-up urine culture needed in patients who respond to therapy 1
• Consider urine culture for patients with symptoms that do not resolve or recur within 2-4 weeks after completing treatment 3

Non-Antibiotic Measures

• Increase fluid intake
• Urinate after sexual activity if infections are related to sexual activity
• Avoid spermicides 1
• Consider vaginal estrogen with or without lactobacillus-containing probiotics for perimenopausal women 1

The evidence clearly shows that despite updated guidelines, there remains low concordance with recommendations for both antibiotic choice and treatment duration in primary care settings 5. Clinicians should be vigilant about following current guidelines to help preserve antimicrobial efficacy and improve patient outcomes.