IDSA Guidelines for Cystitis Treatment
According to the 2011 Infectious Diseases Society of America (IDSA) guidelines, nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for 5 days) is recommended as first-line therapy for acute uncomplicated cystitis due to minimal resistance and limited collateral damage, with efficacy comparable to trimethoprim-sulfamethoxazole 1.
First-Line Treatment Options
Nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for 5 days) is a first-line agent with clinical cure rates of 88-93% and bacterial cure rates of 81-92% 1.
Trimethoprim-sulfamethoxazole (160/800 mg twice daily for 3 days) is appropriate first-line therapy only when local resistance rates of uropathogens are known to be <20% or the infecting strain is confirmed susceptible 1.
Fosfomycin trometamol (3 g single dose) is an appropriate first-line option with minimal resistance and limited collateral damage, though it may have slightly lower efficacy compared to standard short-course regimens 1, 2.
Pivmecillinam (400 mg twice daily for 3-7 days) is recommended in regions where available (primarily European countries, not available in North America) 1.
Alternative Treatment Options
Fluoroquinolones (ofloxacin, ciprofloxacin, norfloxacin, levofloxacin) are highly effective in 3-day regimens but should be reserved as alternative agents due to their propensity for collateral damage 1.
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.
Other β-lactams like cephalexin are less studied but may be appropriate in certain settings 1.
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.
Comparative Efficacy
Nitrofurantoin has shown similar clinical cure rates to ciprofloxacin (93% vs 95%) and trimethoprim-sulfamethoxazole (93% vs 95%) 1.
Fosfomycin has demonstrated clinical cure rates of approximately 90%, but microbiological cure rates may be lower (78%) compared to nitrofurantoin (86%) 1, 2.
Trimethoprim-sulfamethoxazole shows significantly reduced efficacy against resistant organisms (clinical cure rates of 41-54% for resistant strains vs 84-88% for susceptible strains) 1.
Special Considerations
For uncomplicated cystitis in women, diagnosis can often be made without an office visit or urine culture 3.
Urine cultures are recommended for women with suspected pyelonephritis, symptoms that don't resolve or recur within 2-4 weeks after treatment, or those presenting with atypical symptoms 4.
Immediate antimicrobial therapy is recommended rather than delayed treatment or symptom management alone 3.
The threshold of 20% resistance prevalence for trimethoprim-sulfamethoxazole is based on expert opinion from clinical, in vitro, and mathematical modeling studies 1.
When choosing an empiric agent, consider local resistance patterns, patient allergies, potential side effects, and cost 1.