Antibiotic Treatment for Uncomplicated UTI
For an otherwise healthy adult with uncomplicated UTI, prescribe nitrofurantoin 100 mg twice daily for 5 days as the first-line treatment. 1, 2
First-Line Treatment Options
Nitrofurantoin is the most strongly recommended first-line agent due to its excellent efficacy, minimal antimicrobial resistance despite over 60 years of use, and favorable side effect profile in short-course therapy. 1, 2 The standard dosing is nitrofurantoin monohydrate/macrocrystals 100 mg orally twice daily for 5 days. 3, 1
Alternative first-line options include:
Fosfomycin 3 g as a single oral dose - offers convenient single-dose administration, though it may have slightly inferior efficacy compared to multi-day regimens. 1, 2
Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days - can be used ONLY if local E. coli resistance rates are below 20%. 3, 1, 2 This is critical because resistance to TMP-SMX has increased markedly in many communities, making it unsuitable for empiric therapy in areas with high resistance. 4, 5
Critical Contraindications for Nitrofurantoin
Do not prescribe nitrofurantoin in the following situations:
- Creatinine clearance less than 60 mL/min 1, 2
- Suspected pyelonephritis (upper tract infection) 1, 2
- Infants under 4 months of age 1
- Last trimester of pregnancy 6
Second-Line Options
If first-line agents cannot be used:
Cephalosporins (e.g., cefadroxil 500 mg twice daily for 3 days) - only if local E. coli resistance is less than 20%. 2
Fluoroquinolones should be avoided as first-line therapy due to high resistance rates, significant collateral damage to normal flora, and serious adverse effects. 2, 4 Reserve these for pyelonephritis or complicated UTIs. 2
Special Populations
For men with uncomplicated UTI:
- Require longer treatment duration of minimum 7 days with either trimethoprim-sulfamethoxazole 160/800 mg twice daily or nitrofurantoin 100 mg twice daily. 2
- Nitrofurantoin is generally not considered a good choice for men in some guidelines due to concerns about tissue penetration. 5
For pyelonephritis (upper tract infection):
- Fluoroquinolones for 5-7 days (ciprofloxacin 500-750 mg twice daily for 7 days or levofloxacin 750 mg once daily for 5 days) are recommended for outpatient management. 1
- Alternatively, trimethoprim-sulfamethoxazole 160/800 mg twice daily for 14 days based on antibiotic susceptibility. 3, 1
When to Obtain Urine Culture
Urine culture is required in these situations:
- All men with UTI symptoms 1, 2
- Women with recurrent UTI 1, 2
- Treatment failure 1, 2
- Symptom recurrence within 2 weeks 1, 2
Management of Treatment Failure
If symptoms persist after completing treatment:
- Obtain urine culture with susceptibility testing 1, 2
- Retreat with a 7-day regimen using a different antibiotic class 1, 2
Common Pitfalls to Avoid
Do not use amoxicillin or ampicillin empirically - high resistance rates make these ineffective. 2
Do not prescribe fluoroquinolones as first-line therapy - their overuse has led to inappropriate utilization and resistance development. 7
Do not use nitrofurantoin for pyelonephritis - it does not achieve adequate tissue levels in the renal parenchyma. 1, 2
Verify local resistance patterns before prescribing TMP-SMX, as resistance exceeds 20% in many communities. 4, 5