What are common antibiotics for treating urinary tract infections (UTIs)?

Common Antibiotics for Urinary Tract Infections (UTIs)

First-line antibiotics for uncomplicated UTIs include nitrofurantoin, trimethoprim-sulfamethoxazole (TMP-SMX), and fosfomycin, which should be selected based on local antibiogram patterns to optimize treatment outcomes while minimizing antimicrobial resistance. 1

First-Line Treatment Options for Uncomplicated UTIs

• Nitrofurantoin - Typically dosed as 50-100 mg four times daily or 100 mg twice daily for 5 days 1
• Trimethoprim-sulfamethoxazole (TMP-SMX) - Standard dosing is 160/800 mg twice daily for 3 days in women 1
• Fosfomycin trometamol - Administered as a single 3g dose, particularly effective for uncomplicated cystitis 1
• Pivmecillinam - Dosed at 400 mg three times daily for 3-5 days (where available) 1

Second-Line Treatment Options

• Cephalosporins (e.g., cefadroxil) - 500 mg twice daily for 3 days, recommended when local E. coli resistance is <20% 1
• Fluoroquinolones - Should be reserved for specific situations due to increasing resistance and potential adverse effects 1
• Amoxicillin-clavulanic acid - An alternative option when first-line agents cannot be used 1

Treatment Duration Considerations

• For uncomplicated cystitis in women, short-course therapy (3-5 days) is generally sufficient 1
• For recurrent UTIs (rUTIs), treatment duration should generally not exceed 7 days 1
• Single-dose antibiotics (except fosfomycin) have been associated with higher rates of bacteriological persistence compared to short-course (3-6 days) or longer-course (7-14 days) therapy 1

Special Population Considerations

Men with UTIs

• Longer treatment duration (7 days) is typically recommended 1, 2
• TMP-SMX (160/800 mg twice daily) is the preferred first-line agent 1, 2
• Fluoroquinolones may be considered based on local susceptibility patterns 1

Complicated UTIs

• Parenteral options may be needed for resistant organisms 1
• Culture-directed therapy is essential for optimal management 1
• For oral treatment failures with resistant organisms, parenteral antibiotics should be used for as short a course as reasonable (generally ≤7 days) 1

Clinical Pearls and Pitfalls

• Always consider local resistance patterns when selecting empiric therapy, as regional variations can significantly impact treatment success 1
• Avoid treating asymptomatic bacteriuria except in pregnant women and patients undergoing invasive urologic procedures 1
• Obtain urine cultures before initiating treatment in patients with recurrent UTIs, treatment failures, or atypical presentations 1, 2
• Fluoroquinolones should be used judiciously due to FDA warnings about serious adverse effects including tendon, muscle, joint, and nerve damage 1, 3
• Antimicrobial stewardship is crucial to balance symptom resolution with minimizing resistance development 1, 4

Approach to Recurrent UTIs

• First-line agents remain the same (nitrofurantoin, TMP-SMX, fosfomycin) but should be guided by culture results 1
• For patients with cultures showing resistance to oral antibiotics, culture-directed parenteral antibiotics may be necessary 1
• Non-antibiotic preventive strategies should be considered before long-term antibiotic prophylaxis 1, 4

By following these evidence-based recommendations and considering local resistance patterns, clinicians can effectively treat UTIs while practicing good antimicrobial stewardship.