What is the recommended treatment for pyelonephritis?

Treatment of Pyelonephritis

Outpatient Treatment (Mild to Moderate Cases)

For uncomplicated acute pyelonephritis in women who do not require hospitalization, oral ciprofloxacin 500 mg twice daily for 7 days is the preferred first-line treatment when local fluoroquinolone resistance is below 10%. 1, 2

First-Line Fluoroquinolone Regimens

• Ciprofloxacin 500 mg orally twice daily for 7 days is highly effective, with clinical cure rates of 97% 1, 3
• Alternative once-daily fluoroquinolone options include:
  • Levofloxacin 750 mg orally once daily for 5 days 1, 2, 4
  • Ciprofloxacin extended-release 1000 mg orally once daily for 7 days 1, 2

Critical Consideration for Fluoroquinolone Resistance

If local fluoroquinolone resistance exceeds 10%, you must administer an initial one-time intravenous dose of a long-acting parenteral antimicrobial before starting oral fluoroquinolone therapy. 1, 2 Options include:

• Ceftriaxone 1 g IV once 1, 2
• Gentamicin 5-7 mg/kg IV once (consolidated 24-hour dose) 1, 2

Alternative Oral Regimen

• Trimethoprim-sulfamethoxazole 160/800 mg (double-strength) orally twice daily for 14 days is appropriate only if the uropathogen is known to be susceptible 1, 2
• If using TMP-SMX empirically when susceptibility is unknown, give an initial IV dose of ceftriaxone 1 g or aminoglycoside first 1
• TMP-SMX has high resistance rates and corresponding treatment failure rates, making it inferior for empirical therapy 1

Inpatient Treatment (Severe Cases or Complications)

For patients requiring hospitalization, initiate intravenous therapy with one of the following regimens based on local resistance patterns: 2

• Fluoroquinolone IV (ciprofloxacin 400 mg IV every 12 hours or levofloxacin 750 mg IV daily) 2, 5
• Aminoglycoside with or without ampicillin (gentamicin 5-7 mg/kg IV once daily) 2
• Extended-spectrum cephalosporin (ceftriaxone 1 g IV every 12-24 hours) 2, 5
• Extended-spectrum penicillin with or without aminoglycoside 2
• Carbapenem (for complicated infections or resistant organisms) 2

Transition to Oral Therapy

Once clinical improvement occurs (typically after 24-48 hours of apyrexia), transition to oral therapy to complete a total treatment duration of 10-14 days for β-lactams or 5-7 days for fluoroquinolones 2

Essential Pre-Treatment Steps

Always obtain urine culture and susceptibility testing before initiating antibiotics in all patients with suspected pyelonephritis. 1, 2 This is non-negotiable for guiding definitive therapy.

• Blood cultures should be reserved for patients with uncertain diagnosis, immunocompromised status, or suspected hematogenous infection 6
• Urine cultures are positive in 90% of patients with acute pyelonephritis 6

Treatment Duration by Antibiotic Class

• Fluoroquinolones: 5-7 days (depending on specific agent) 1, 2, 3
• Trimethoprim-sulfamethoxazole: 14 days 1, 2
• β-lactams: 10-14 days 2

Indications for Hospitalization

Admit patients with any of the following: 6

• Complicated infections (anatomic/functional abnormalities, immunosuppression)
• Sepsis or hemodynamic instability
• Persistent vomiting preventing oral intake
• Failed outpatient treatment
• Extremes of age with severe illness
• Pregnancy

Common Pitfalls to Avoid

Do not use oral β-lactams (amoxicillin, ampicillin, cephalexin) as empirical monotherapy without an initial parenteral dose due to high resistance rates and inferior efficacy 1, 2

Do not use fluoroquinolones empirically in areas with >10% resistance without adding an initial parenteral agent dose. 1, 2 This is a critical error that leads to treatment failure.

Do not fail to adjust therapy based on culture results. 2 Initial empirical therapy must be tailored once susceptibility data are available.

Do not use inadequate treatment duration, especially with β-lactam agents (minimum 10-14 days required). 2

Follow-Up

• Repeat urine culture 10-14 days after completion of antibiotic therapy to confirm eradication 1, 6
• If no clinical improvement within 48-72 hours, repeat blood and urine cultures and consider imaging (contrast-enhanced CT) to evaluate for complications such as abscess or obstruction 6, 7

Special Populations

In elderly patients, monitor closely for adverse effects, particularly with aminoglycosides (nephrotoxicity, ototoxicity) and fluoroquinolones (tendon disorders, neuropsychiatric effects, arrhythmias). 2, 8