What is the recommended antibiotic treatment for acute uncomplicated cystitis?

Recommended Antibiotic Treatment for Acute Uncomplicated Cystitis

Nitrofurantoin monohydrate/macrocrystals 100 mg twice daily for 5 days is the first-line treatment for acute uncomplicated cystitis, with clinical cure rates of 88-93% and minimal resistance patterns. 1

First-Line Treatment Options

The Infectious Diseases Society of America (IDSA) recommends three first-line agents, listed in order of preference 1:

• Nitrofurantoin monohydrate/macrocrystals: 100 mg twice daily for 5 days - This is the preferred first-line agent due to minimal resistance, limited collateral damage to gut flora, and efficacy comparable to other agents 1, 2, 3

  • Clinical cure rates: 88-93% 1
  • Bacterial cure rates: 81-92% 1
  • Equivalent efficacy to ciprofloxacin (93% vs 95%) and trimethoprim-sulfamethoxazole (93% vs 95%) 1

• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 3 days - Use ONLY when local E. coli resistance rates are documented to be <20% or when the infecting strain is confirmed susceptible 1, 2

  • Clinical cure rates drop dramatically against resistant strains (41-54% vs 84-88% for susceptible strains) 1
  • This 20% resistance threshold is based on expert opinion from clinical, in vitro, and mathematical modeling studies 1

• Fosfomycin trometamol: 3 g single oral dose - An appropriate alternative with minimal resistance, though slightly inferior efficacy 1, 2, 4

  • Clinical cure rate: approximately 90% 1
  • Microbiological cure rate: 78% (lower than nitrofurantoin's 86%) 1
  • FDA-approved specifically for uncomplicated cystitis in women ≥18 years 4

• Pivmecillinam: 400 mg twice daily for 3-7 days - Recommended where available (primarily European countries, not available in North America) 1

Alternative (Second-Line) Treatment Options

Use these agents only when first-line options cannot be used 1:

• Fluoroquinolones (ciprofloxacin, levofloxacin, ofloxacin, norfloxacin): 3-day regimens are highly effective (95% clinical cure rate) but should be reserved for more serious infections due to their propensity for promoting antimicrobial resistance and collateral damage 1, 2, 5

• β-Lactam agents (amoxicillin-clavulanate, cefdinir, cefaclor, cefpodoxime-proxetil): 3-7 day regimens have generally inferior efficacy and more adverse effects compared to first-line agents 1, 2

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

Treatment Algorithm

Step 1: Confirm diagnosis of acute uncomplicated cystitis (dysuria, frequency, urgency in otherwise healthy non-pregnant women without fever, flank pain, or comorbidities) 5, 6

Step 2: Check for contraindications to nitrofurantoin:

• Suspected early pyelonephritis (avoid nitrofurantoin) 3
• Creatinine clearance <30 mL/min
• Perinephric abscess 3

Step 3: Prescribe nitrofurantoin 100 mg twice daily for 5 days if no contraindications exist 1, 2, 3

Step 4: If nitrofurantoin cannot be used:

• Consider fosfomycin 3 g single dose 1, 2
• Consider trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days ONLY if local resistance <20% 1, 2

Step 5: Reserve fluoroquinolones and β-lactams for situations where first-line agents are contraindicated or ineffective 1, 2

Special Considerations for Patient Allergies

For patients with penicillin allergy:

• Nitrofurantoin remains first-line (100 mg twice daily for 5 days) 2
• Fosfomycin is second-line (3 g single dose) 2
• Trimethoprim-sulfamethoxazole is third-line if local resistance <20% 2

For patients with both penicillin AND sulfa allergies:

• Nitrofurantoin is preferred 1, 2
• Fosfomycin is the alternative 1, 2
• Fluoroquinolones only if above options unavailable 1

Follow-Up Recommendations

• Routine post-treatment urinalysis or urine cultures are NOT indicated for asymptomatic patients 2, 3

• Obtain urine culture with susceptibility testing if 2, 3:

  • Symptoms do not resolve by end of treatment
  • Symptoms recur within 2 weeks
  • Patient presents with atypical symptoms

• Retreatment: Consider a 7-day regimen using a different agent if symptoms persist or recur 2, 3

Common Pitfalls to Avoid

• Overprescribing fluoroquinolones: Despite their 95% efficacy, fluoroquinolones should be preserved for more serious infections to prevent resistance development 1, 5, 7

• Excessive treatment duration: Studies show 82% of TMP-SMX prescriptions, 73% of nitrofurantoin prescriptions, and 71% of fluoroquinolone prescriptions exceed guideline-recommended durations 7

• Using trimethoprim-sulfamethoxazole without knowing local resistance patterns: This can result in treatment failure rates of 46-59% when resistance exceeds 20% 1

• Prescribing β-lactams as first-line therapy: These agents have inferior efficacy compared to nitrofurantoin, trimethoprim-sulfamethoxazole, and fosfomycin 1, 5