Treatment and Dosage for UTI
For uncomplicated cystitis in women, first-line treatment is fosfomycin 3g single dose, nitrofurantoin 100mg twice daily for 5 days, or pivmecillinam 400mg three times daily for 3-5 days 1.
Uncomplicated Cystitis (Lower UTI in Women)
First-Line Options
- Fosfomycin trometamol: 3g single dose (one-time treatment)
- Nitrofurantoin: 100mg twice daily for 5 days
- Pivmecillinam: 400mg three times daily for 3-5 days
These agents are preferred because they minimize collateral damage to normal flora, have favorable resistance patterns, and spare broader-spectrum agents for more serious infections 1, 2.
Alternative Options (if first-line unavailable or contraindicated)
- Trimethoprim-sulfamethoxazole (TMP-SMX): 160/800mg twice daily for 3 days
- Only use if local E. coli resistance is <20%
- Avoid in first trimester of pregnancy
- Cephalosporins (e.g., cefadroxil): 500mg twice daily for 3 days
- Only if local resistance <20%
- Fluoroquinolones: 3-day course
Important Caveats
- Symptomatic therapy alone (ibuprofen) may be considered for mild symptoms in consultation with the patient, though this requires shared decision-making 1
- Men with cystitis: Use TMP-SMX 160/800mg twice daily for 7 days (longer duration than women) 1
- No routine post-treatment cultures needed if symptoms resolve 1
Uncomplicated Pyelonephritis (Upper UTI)
Oral Therapy (Outpatient)
For patients who can tolerate oral medications and are clinically stable:
- Ciprofloxacin: 500-750mg twice daily for 7 days
- Levofloxacin: 750mg once daily for 5 days
- TMP-SMX: 160/800mg twice daily for 14 days (if susceptible)
- Cefpodoxime: 200mg twice daily for 10 days
- Ceftibuten: 400mg once daily for 10 days
Critical point: Fluoroquinolones are preferred only when local resistance is <10%. If using oral cephalosporins empirically, give an initial IV dose of ceftriaxone first 1, 2.
Parenteral Therapy (Hospitalized/Severe)
Initial IV treatment options:
- Ceftriaxone: 1-2g once daily (preferred for most cases)
- Ciprofloxacin: 400mg twice daily IV
- Levofloxacin: 750mg once daily IV
- Cefepime: 1-2g twice daily
- Piperacillin-tazobactam: 3.375-4.5g three times daily
- Gentamicin: 5mg/kg once daily
- Amikacin: 15mg/kg once daily
Reserve carbapenems and novel agents (meropenem, ceftolozane-tazobactam, ceftazidime-avibactam) only for patients with known multidrug-resistant organisms 1.
Complicated UTI
For complicated UTI with clinical improvement, shorter courses (5-7 days of fluoroquinolone or 7 days of non-fluoroquinolone) are as effective as 10-14 day courses 4.
Key Exception
Men with febrile UTI where acute bacterial prostatitis is suspected require 10-14 days of treatment 4. This is the single most important distinction when shortening therapy.
Treatment Selection
Use the same agents as pyelonephritis, but:
- Tailor to local resistance patterns
- Consider risk factors for multidrug resistance (recent hospitalization, recent antibiotics, healthcare exposure)
- Use antipseudomonal agents only when risk factors present 2
Critical Clinical Pitfalls
When NOT to Use Short Courses
- Suspected or confirmed prostatitis in men
- Presence of obstruction or abscess
- Immunocompromised patients
- Pregnancy
- Meningitis not excluded (especially neonates)
When to Obtain Urine Culture
- Suspected pyelonephritis
- Symptoms not resolving or recurring within 4 weeks
- Atypical symptoms
- Pregnancy
- Complicated UTI
- Men with any UTI 1
Resistance Considerations
Do NOT use empirically if local resistance >20%:
- TMP-SMX
- Fluoroquinolones
- First-generation cephalosporins
For ESBL-producing organisms, oral options include nitrofurantoin, fosfomycin, and pivmecillinam for cystitis only. Pyelonephritis requires parenteral therapy with carbapenems or newer beta-lactam combinations 3, 5.