What are the treatment options for urinary tract infections (UTIs)?

Treatment of Urinary Tract Infections

For uncomplicated UTIs in adults, first-line treatment is nitrofurantoin 100 mg twice daily for 5 days, fosfomycin 3 g single dose, or trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days (only if local resistance <20%). 1

Uncomplicated Cystitis in Adults

First-Line Agents

The choice among first-line agents depends on local resistance patterns and patient-specific factors:

• Nitrofurantoin monohydrate/macrocrystals 100 mg twice daily for 5 days is preferred due to minimal resistance rates and low collateral damage to normal flora 1, 2
• Fosfomycin trometamol 3 g as a single dose offers convenient single-dose administration, though with slightly lower efficacy than other first-line options 1, 2
• Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days should only be used if local resistance rates are <20% or if the organism is known to be susceptible 1, 3
• Pivmecillinam 400 mg twice daily for 5 days is an alternative but has lower efficacy and should be avoided if early pyelonephritis is suspected 1

Agents to Avoid as First-Line

Fluoroquinolones should be reserved for more invasive infections such as pyelonephritis, not uncomplicated cystitis, despite their effectiveness 1, 2. This preserves these agents for complicated infections and reduces resistance development 4.

Beta-lactam agents (amoxicillin-clavulanate, cefpodoxime) are less effective as empirical first-line therapy compared to the recommended agents 2.

Important Considerations

• Urine culture is not routinely needed for uncomplicated cystitis in women, but should be obtained when pyelonephritis is suspected, symptoms persist or recur within 4 weeks, or in cases of treatment failure 1
• Immediate antimicrobial therapy is superior to delayed treatment or symptom management with ibuprofen alone 2
• Do not treat asymptomatic bacteriuria except in pregnant women or before invasive urologic procedures, as treatment increases antimicrobial resistance risk 1

Acute Pyelonephritis

For uncomplicated pyelonephritis in hemodynamically stable patients:

Parenteral Therapy Options

• Fluoroquinolones (if local resistance <10%): ciprofloxacin 400 mg IV twice daily or levofloxacin 750 mg IV once daily 1
• Ceftriaxone 1-2 g IV once daily 1
• Gentamicin 5 mg/kg IV once daily 1

Oral Step-Down Therapy

Once hemodynamically stable and afebrile, transition to:

• Ciprofloxacin 500-750 mg twice daily for 7 days total 1
• Levofloxacin 750 mg once daily for 5 days total 1
• Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 14 days total 1
• Cefpodoxime 200 mg twice daily for 10 days total 1

The standard duration is 7 days for most cases, extended to 14 days in men when prostatitis cannot be excluded 1.

Special Populations

Men with UTI

Treat for 7 to 14 days using the same agents as for women, though limited observational data support this duration 2. Consider prostatitis and extend treatment to 14 days if it cannot be excluded 1.

Women with Diabetes

Women with diabetes without voiding abnormalities should be treated identically to women without diabetes for acute cystitis 2.

Recurrent UTIs (≥3 per year or ≥2 in 6 months)

For prevention strategies:

• Postmenopausal women: Initiate vaginal estrogen with or without lactobacillus-containing probiotics 5
• Premenopausal women with post-coital infections: Low-dose antibiotic within 2 hours of sexual activity for 6-12 months 5
• Premenopausal women with infections unrelated to sexual activity: Low-dose daily antibiotic prophylaxis 5
• Non-antibiotic alternatives: Methenamine hippurate and/or lactobacillus-containing probiotics 5

Obtain urine culture before initiating treatment for each recurrent episode 5, 1. Patient-initiated (self-start) therapy may be offered to reliable patients who can obtain specimens before starting therapy 5.

Preferred prophylactic antibiotics: Nitrofurantoin 50 mg, trimethoprim-sulfamethoxazole 40/200 mg, or trimethoprim 100 mg daily, chosen based on prior susceptibility patterns and avoiding fluoroquinolones 5.

Pediatric UTIs (2-24 months)

Route of Administration

Oral and parenteral routes are equally efficacious for initiating treatment 5. Base the choice on practical considerations: toxic appearance, inability to retain oral intake, or concerns about compliance warrant parenteral administration 5.

Antibiotic Options

Oral agents: Amoxicillin-clavulanate 20-40 mg/kg/day in 3 doses, trimethoprim-sulfamethoxazole 6-12 mg/kg trimethoprim per day in 2 doses, or cephalosporins (cefixime 8 mg/kg/day in 1 dose, cefpodoxime 10 mg/kg/day in 2 doses) 5

Parenteral agents: Ceftriaxone 75 mg/kg every 24 hours, cefotaxime 150 mg/kg/day divided every 6-8 hours, or gentamicin 7.5 mg/kg/day divided every 8 hours 5

Do not use nitrofurantoin in febrile infants, as it does not achieve adequate parenchymal and serum concentrations to treat pyelonephritis or urosepsis 5.

Treatment duration is 7 to 14 days total, regardless of initial route 5.

Key Pitfalls to Avoid

• Avoid treating asymptomatic bacteriuria in non-pregnant patients, as this fosters resistance and increases recurrent UTI episodes 5, 1
• Do not classify recurrent UTIs as "complicated" unless true complicating factors exist (structural abnormalities, immunosuppression, pregnancy), as this leads to unnecessary broad-spectrum antibiotic use 5
• Know local resistance patterns before selecting empiric therapy, particularly for trimethoprim-sulfamethoxazole and cephalexin, which show substantial geographic variability 5
• If symptoms persist despite treatment, repeat urine culture to assess for ongoing bacteriuria before prescribing additional antibiotics 5