What antibiotics are used to treat hemorrhagic cystitis complicated by a bacterial infection?

Antibiotics for Hemorrhagic Cystitis with Bacterial Superinfection

When hemorrhagic cystitis is complicated by bacterial infection, treat the bacterial component with standard cystitis antibiotics while managing the hemorrhagic component supportively—nitrofurantoin 100 mg twice daily for 5 days is first-line if eGFR >30 mL/min, or fosfomycin 3 g single dose if renal function is impaired. 1, 2

Critical Context: Hemorrhagic Cystitis is Usually Non-Infectious

Hemorrhagic cystitis typically results from chemotherapy (cyclophosphamide), radiation, or viral infections (BK virus, adenovirus), not bacterial pathogens. 3 The primary management focuses on hyperhydration, bladder irrigation, transfusions, and pain control—not antibiotics. 3, 4 Antibiotics are only indicated when there is documented bacterial superinfection with positive urine cultures showing significant bacterial growth.

First-Line Antibiotic Selection (When Bacterial Infection Confirmed)

For Normal Renal Function (eGFR >30 mL/min):

• Nitrofurantoin monohydrate/macrocrystals 100 mg twice daily for 5 days is the preferred choice due to minimal resistance patterns and limited collateral damage to normal flora. 1, 2
• This provides clinical cure rates of 90-91% for E. coli cystitis, the most common uropathogen. 1

For Impaired Renal Function (eGFR <30 mL/min):

• Fosfomycin trometamol 3 g as a single oral dose becomes the preferred option, as it provides adequate urinary concentrations without dose adjustment and avoids nitrofurantoin toxicity in renal impairment. 1
• Fosfomycin achieves clinical cure rates of 90-91% and does not require dose adjustment for renal impairment. 1

Alternative Options Based on Susceptibility

If Local Resistance Permits:

• Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days can be used only if local E. coli resistance rates are below 20% or if the specific isolate is known to be susceptible. 2
• Rising resistance rates have significantly limited its utility as empiric therapy. 2

Second-Line Options (Reserve for Specific Situations):

• Fluoroquinolones (ciprofloxacin 500 mg twice daily for 7 days or levofloxacin 750 mg once daily for 5 days) should be reserved for situations where first-line agents cannot be used, despite their high efficacy, to preserve them for more serious infections. 5, 2
• For complicated UTIs with hemorrhagic cystitis, fluoroquinolones at appropriate dosing (ciprofloxacin 500 mg twice daily, levofloxacin 500 mg once daily, or gatifloxacin 400 mg once daily) may be necessary. 5, 6

Avoid These Agents:

• β-lactams (amoxicillin-clavulanate, cephalosporins) have inferior efficacy for cystitis, with clinical cure rates of only 58% compared to 77% with fluoroquinolones, even against susceptible strains. 2, 7
• Amoxicillin or ampicillin alone should never be used empirically due to very high resistance rates worldwide. 2

Essential Diagnostic Steps

• Obtain urine culture with susceptibility testing before initiating antibiotics in patients with hemorrhagic cystitis to confirm bacterial infection and guide therapy, as this is a complicated clinical scenario. 1
• Blood cultures are indicated if there are signs of systemic infection or bacteremia. 5
• Distinguish between sterile hemorrhagic cystitis (viral, chemical, radiation-induced) and bacterial superinfection—only the latter requires antibiotics. 3, 4

Treatment Algorithm

1. Confirm bacterial infection with urine culture showing ≥10² CFU/mL of uropathogens 7
2. Assess renal function:
   • If eGFR >30 mL/min → Nitrofurantoin 100 mg twice daily for 5 days 1, 2
   • If eGFR <30 mL/min → Fosfomycin 3 g single dose 1
3. If first-line agents contraindicated → Consider fluoroquinolones (ciprofloxacin 500 mg twice daily for 7 days) 5, 2
4. Adjust therapy based on culture results and clinical response 5
5. Continue supportive management of hemorrhagic component (hydration, irrigation, transfusions) regardless of antibiotic choice 3, 4

Critical Pitfalls to Avoid

• Do not use nitrofurantoin if eGFR <30 mL/min—this leads to treatment failure and increased toxicity due to inadequate urinary drug concentrations. 1
• Do not prescribe antibiotics empirically for hemorrhagic cystitis without confirming bacterial infection—most cases are non-bacterial and antibiotics provide no benefit while promoting resistance. 3, 4
• Do not use fluoroquinolones as first-line therapy—reserve these for situations where first-line agents fail or cannot be used, to preserve their efficacy for serious infections. 2
• Do not use β-lactams empirically—they have significantly inferior cure rates (58% vs 77%) even against susceptible organisms. 7
• Do not rely solely on antibiotics—the hemorrhagic component requires aggressive supportive care including hydration, bladder irrigation, and transfusion support. 3, 4