What are the treatment guidelines for acute bacterial cystitis?

Treatment Guidelines for Acute Bacterial Cystitis

Nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for 5 days) is the preferred first-line therapy for acute uncomplicated cystitis due to minimal resistance and limited collateral damage to normal flora. 1, 2

First-Line Treatment Options

• Nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for 5 days) is recommended as first-line therapy with clinical cure rates of 88-93% 1
• Trimethoprim-sulfamethoxazole (160/800 mg twice daily for 3 days) is appropriate only when local resistance rates are known to be <20% or the infecting strain is confirmed susceptible 3, 1
• Fosfomycin trometamol (3 g single dose) is an appropriate alternative first-line option, though it may have slightly inferior efficacy compared to other regimens 3, 1
• Pivmecillinam (400 mg twice daily for 5 days) is recommended in regions where available (primarily European countries) 1, 2

Treatment Selection Algorithm

1. First choice: Nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for 5 days) 3, 1
2. If nitrofurantoin contraindicated (e.g., CKD with eGFR <30 ml/min): Fosfomycin trometamol (3 g single dose) 1, 4
3. If local resistance to TMP-SMX <20%: Consider trimethoprim-sulfamethoxazole (160/800 mg twice daily for 3 days) 3, 1
4. If all first-line options unavailable: Consider β-lactams or fluoroquinolones as alternatives, recognizing their limitations 1, 2

Alternative Treatment Options

• Fluoroquinolones (ciprofloxacin, levofloxacin) are highly effective in 3-day regimens but should be reserved as alternative agents due to their propensity for collateral damage and risk of promoting resistance 1, 5
• β-Lactam agents (amoxicillin-clavulanate, cefdinir, cefaclor, cefpodoxime-proxetil) in 3-7 day regimens should be used only when first-line agents cannot be used, as they generally have inferior efficacy and more adverse effects 1, 6

Special Considerations

• For patients with CKD: Nitrofurantoin should be avoided when eGFR is <30 ml/min due to reduced efficacy and increased toxicity 4
• For patients with sulfa and penicillin allergies: Nitrofurantoin (if eGFR >30 ml/min) or fosfomycin are preferred options 4
• Urine culture is not routinely needed for uncomplicated cystitis but should be performed if symptoms do not resolve or recur within 2-4 weeks after treatment 2, 6

Treatments to Avoid

• Amoxicillin or ampicillin should not be used for empirical treatment due to poor efficacy and high prevalence of antimicrobial resistance worldwide 1, 2
• Using fluoroquinolones as first-line therapy despite their high efficacy, as this promotes resistance to these important agents needed for more serious infections 1, 2

Common Pitfalls to Avoid

• Prescribing trimethoprim-sulfamethoxazole empirically without knowledge of local resistance patterns 3, 7
• Using nitrofurantoin in patients with severely impaired renal function (eGFR <30 ml/min) 4
• Prescribing longer courses of antibiotics than necessary (e.g., 10-day courses when shorter durations are effective) 8
• Failing to adjust therapy if symptoms persist, which may indicate resistance to the chosen antibiotic 2

Treatment Duration

• Nitrofurantoin requires 5 days of treatment 3, 1
• Trimethoprim-sulfamethoxazole is effective with 3 days of treatment 3, 1
• Fosfomycin is administered as a single 3 g dose 3, 1
• Fluoroquinolones are effective in 3-day regimens 1, 6
• β-Lactams require 3-7 days of treatment 1, 6