What is the recommended treatment for bacterial cystitis?

Treatment for Bacterial Cystitis

Nitrofurantoin monohydrate/macrocrystals 100 mg twice daily for 5 days is the recommended first-line treatment for acute uncomplicated bacterial cystitis in most patients. 1

First-Line Treatment Options

The Infectious Diseases Society of America prioritizes nitrofurantoin as first-line therapy due to minimal resistance patterns and limited collateral damage to normal flora, with clinical cure rates of 88-93% and bacterial cure rates of 81-92%. 1

Alternative first-line agents include:

• Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days - Use ONLY when local E. coli resistance is documented to be <20% or when susceptibility is confirmed. 1, 2 This threshold is critical because efficacy drops dramatically from 84-88% for susceptible strains to only 41-54% for resistant organisms. 1, 2

• Fosfomycin trometamol 3 g as a single dose - Appropriate alternative with clinical cure rates of approximately 90%, though microbiological cure rates may be slightly lower (78%) compared to nitrofurantoin (86%). 1 This agent requires no dose adjustment for renal impairment and is particularly useful when eGFR is <30 mL/min. 3

• Pivmecillinam 400 mg twice daily for 3-7 days - Recommended in European countries where available, but not accessible in North America. 1

Second-Line Treatment Options

Fluoroquinolones should be reserved as alternative agents only when first-line options cannot be used. 1 Despite their high efficacy in 3-day regimens (ciprofloxacin, levofloxacin, ofloxacin, norfloxacin), they cause significant collateral damage to normal flora and promote resistance. 1 These agents must be preserved for more serious infections like pyelonephritis. 2

β-Lactam agents (amoxicillin-clavulanate, cefdinir, cefaclor, cefpodoxime-proxetil) in 3-7 day regimens have inferior efficacy and more adverse effects compared to first-line agents, and should only be used when other options are contraindicated. 1

Treatments to Avoid

Never use amoxicillin or ampicillin for empirical treatment due to poor efficacy and high prevalence of antimicrobial resistance worldwide. 1, 4

Special Clinical Scenarios

Patients with Chronic Kidney Disease

• If eGFR >30 mL/min: Nitrofurantoin 100 mg twice daily for 5 days remains appropriate. 3
• If eGFR <30 mL/min: Avoid nitrofurantoin due to reduced efficacy and increased toxicity risk; use fosfomycin trometamol 3 g single dose instead. 3
• Always obtain urine culture with susceptibility testing in CKD patients before initiating therapy to guide appropriate antibiotic selection. 3

Patients with Penicillin and Sulfa Allergies

• First choice: Fosfomycin trometamol 3 g single dose. 1
• Second choice: Nitrofurantoin 100 mg twice daily for 5 days (if no contraindications). 1
• Avoid cephalosporins in patients with documented penicillin allergy without formal allergy testing, despite lower cross-reactivity rates (2-4%) than historically believed. 3
• Last resort: Fluoroquinolones for 3 days, recognizing their limitations and resistance promotion concerns. 1

Treatment Duration Specifics

• Nitrofurantoin: 5-7 days required for optimal efficacy. 1
• Trimethoprim-sulfamethoxazole: 3 days effective for women; 7 days needed for men. 1, 2
• Fluoroquinolones: 3-day regimens are effective. 1
• β-Lactams: 3-7 days required. 1

Critical Pitfalls to Avoid

• Do not prescribe trimethoprim-sulfamethoxazole empirically when local resistance exceeds 20%, or in patients who have used it in the preceding 3-6 months, or who have traveled outside the United States recently. 2 These factors independently predict resistance. 2

• Do not use fluoroquinolones as first-line therapy despite their excellent efficacy, as this promotes resistance to agents needed for serious infections. 1, 2

• Do not prescribe longer durations than recommended. Each additional day beyond recommended duration carries a 5% increased risk for antibiotic-associated adverse events without additional benefits. 2

• Do not use nitrofurantoin when eGFR <30 mL/min as this leads to treatment failure and increased toxicity. 3

• Do not rely on hospital antibiograms for community-acquired cystitis, as they overestimate community resistance rates. 2 Local outpatient surveillance data is more accurate for guiding empiric therapy. 2