Treatment of Urinary Tract Infections in Females
For acute uncomplicated UTI in non-pregnant women, treat with nitrofurantoin 100mg twice daily for 5 days, fosfomycin 3g single dose, or trimethoprim-sulfamethoxazole 160/800mg twice daily for 3 days—but only use TMP-SMX if local resistance rates are <20%. 1
First-Line Antibiotic Selection
The choice of empiric therapy depends critically on local resistance patterns and recent antibiotic exposure:
Nitrofurantoin 100mg twice daily for 5 days is the preferred first-line agent, with extremely low risk of serious pulmonary (0.001%) or hepatic (0.0003%) toxicity 1
Fosfomycin 3g as a single dose is an excellent alternative, particularly for patients who prefer single-dose therapy 1, 2
Trimethoprim-sulfamethoxazole 160/800mg twice daily for 3 days can be used only if local E. coli resistance is <20% and the patient has not recently been exposed to this antibiotic 3, 4
Avoid fluoroquinolones and cephalosporins as first-line agents unless other options are contraindicated, as these are reserved for more complicated infections and their overuse drives antimicrobial resistance 1
Critical Pre-Treatment Steps
Obtain urine culture and sensitivity before initiating treatment in women with recurrent UTIs (≥2 infections in 6 months or ≥3 in 12 months) to document microbial confirmation 5
For first-time or infrequent UTIs in otherwise healthy women, empiric treatment without culture is acceptable if symptoms are classic (acute-onset dysuria with urgency/frequency) 5
Dysuria has >90% accuracy for UTI in young women when vaginal irritation or discharge is absent 5
Treatment Duration
Keep treatment duration short—no longer than 5-7 days for uncomplicated cystitis—to minimize antimicrobial resistance 1
Five-day courses are standard for nitrofurantoin 1
Single-dose fosfomycin is sufficient for uncomplicated cases 1, 2
Special Populations Requiring Different Approaches
Pregnant Women (Any Trimester)
First-line: Nitrofurantoin 50-100mg four times daily for 7 days (avoid in third trimester near delivery) 7
Alternative: Fosfomycin 3g single dose for uncomplicated lower UTI 7
Cephalexin 500mg four times daily for 7-14 days is the preferred alternative when nitrofurantoin is contraindicated 7
Never use trimethoprim-sulfamethoxazole in first trimester (teratogenic risk) or last trimester (kernicterus risk) 7
Never use fluoroquinolones during pregnancy due to fetal cartilage development concerns 7
Always obtain urine culture before treatment and treat even asymptomatic bacteriuria, as untreated bacteriuria increases pyelonephritis risk 20-30 fold (from 1-4% to 20-35%) 7
Postmenopausal Women
- Same antibiotic choices as above, but consider vaginal estrogen cream as adjunctive prevention for recurrent infections 6
Prevention Strategies for Recurrent UTIs
Before resorting to antibiotic prophylaxis, implement behavioral modifications:
Increase fluid intake to promote frequent urination 1
Void after sexual intercourse 1
Avoid sequential anal and vaginal intercourse 1
Consider discontinuing spermicide use if applicable 5
If behavioral modifications fail:
Methenamine hippurate is the preferred non-antibiotic prophylaxis option 1
Cranberry products containing ≥36mg/day proanthocyanidin A may be offered, though evidence is weak 5, 1
Continuous antibiotic prophylaxis for 6-12 months should only be considered after non-antimicrobial measures fail, using low-dose nitrofurantoin, TMP-SMX, or cephalexin based on prior culture sensitivities 5
Patient-initiated self-start treatment can be offered to select patients with recurrent UTIs who recognize their symptoms early, while awaiting culture results 5
Critical Pitfalls to Avoid
Never treat asymptomatic bacteriuria in non-pregnant, non-surgical patients—this fosters resistance and increases recurrence risk 1
Never obtain cystoscopy or upper tract imaging routinely in women with recurrent uncomplicated UTI 5
Do not use fluoroquinolones empirically for simple cystitis, as this drives resistance to agents needed for pyelonephritis and complicated infections 1, 2
Avoid prolonged antibiotic courses (>5-7 days) for uncomplicated UTI, as this increases resistance without improving outcomes 1
Do not ignore local antibiogram data—resistance patterns vary significantly by region, and empiric choices must reflect local susceptibility 5, 2
Avoid broad-spectrum antibiotics unnecessarily, as they disrupt normal vaginal and fecal flora, predisposing to recurrent infections 1
When to Suspect Complicated UTI Requiring Different Management
Refer for further evaluation if the patient has:
- Fever or flank pain (suggesting pyelonephritis) 5
- Structural/functional urinary tract abnormalities 5
- Immunosuppression 5
- Indwelling catheter or intermittent self-catheterization 5
- Diabetes, neurological disease, or spinal cord injury 5
- Symptoms persisting >48-72 hours despite appropriate therapy 2
These patients require longer treatment courses (7-14 days), often with broader-spectrum agents, and may need imaging studies 5, 2