What is the recommended treatment for pyelonephritis?

Treatment of Pyelonephritis

For outpatient treatment of acute pyelonephritis, use oral ciprofloxacin 500 mg twice daily for 7 days or levofloxacin 750 mg once daily for 5 days as first-line therapy if local fluoroquinolone resistance is below 10%. 1, 2

Initial Assessment

• Always obtain urine culture and susceptibility testing before initiating antibiotics to guide definitive therapy and adjust treatment based on results. 1, 2
• Tailor empirical therapy based on local resistance patterns, as fluoroquinolone resistance rates vary significantly by region. 1, 2

Outpatient Treatment Algorithm

When Fluoroquinolone Resistance is <10%:

• Ciprofloxacin 500 mg orally twice daily for 7 days is the preferred first-line option. 1, 2, 3
• Alternative: Levofloxacin 750 mg orally once daily for 5 days. 1, 2, 4
• Alternative once-daily option: Ciprofloxacin 1000 mg extended-release for 7 days. 1

When Fluoroquinolone Resistance is ≥10%:

• Give one initial IV dose of ceftriaxone 1g or an aminoglycoside, then follow with oral fluoroquinolone therapy. 1, 2
• This combination approach overcomes the resistance threshold while allowing oral step-down therapy. 1, 2

If Pathogen Susceptibility is Known:

• Trimethoprim-sulfamethoxazole 160/800 mg (double-strength) twice daily for 14 days is appropriate only if the uropathogen is confirmed susceptible. 1, 2
• Note the longer duration required (14 days vs. 5-7 days for fluoroquinolones). 1

Inpatient Treatment

Indications for Hospitalization:

• Complicated infections, sepsis, persistent vomiting, failed outpatient treatment, extremes of age, or other high-risk conditions warrant admission. 1

Initial IV Antibiotic Options:

• Fluoroquinolone (ciprofloxacin or levofloxacin) IV. 1, 2
• Extended-spectrum cephalosporin (e.g., ceftriaxone 1g IV every 12-24 hours or cefepime). 1, 2
• Aminoglycoside (e.g., gentamicin 5-7 mg/kg once daily) with or without ampicillin. 1
• Carbapenem for suspected multidrug-resistant organisms. 1, 2

Step-Down to Oral Therapy:

• Switch to oral antibiotics once the patient can tolerate oral intake and shows clinical improvement, guided by culture results. 2
• Oral β-lactams are less effective than fluoroquinolones but can be used if the pathogen is susceptible. 1, 2

Treatment Duration by Antibiotic Class

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

Special Populations

Elderly Patients:

• Monitor closely for adverse effects, particularly with aminoglycosides (nephrotoxicity) and fluoroquinolones (tendon disorders, neuropsychiatric effects). 1
• Up to 50% of diabetic patients may not present with typical flank tenderness, making diagnosis more challenging. 2

Patients with Renal Impairment:

• Dose adjustment is required for many antibiotics; reduce standard dose by approximately 30-50% for moderate renal impairment. 2
• Use aminoglycosides with extreme caution and careful monitoring to avoid nephrotoxicity. 2

High-Risk Populations:

• Patients with diabetes, anatomic abnormalities, vesicoureteral reflux, renal obstruction, pregnancy, nosocomial infection, transplant recipients, or immunosuppression require closer monitoring and may need inpatient therapy. 2

Common Pitfalls to Avoid

• Never start antibiotics without obtaining urine cultures first, as this prevents appropriate adjustment of therapy. 1, 2
• Do not use fluoroquinolones empirically in areas with >10% resistance without adding an initial parenteral dose of ceftriaxone or aminoglycoside. 1, 2
• Do not use oral β-lactams as monotherapy without an initial parenteral dose, as they have inferior efficacy compared to fluoroquinolones. 1, 2
• Do not use nitrofurantoin or oral fosfomycin for pyelonephritis, as there is insufficient data regarding efficacy. 2
• Avoid inadequate treatment duration, especially with β-lactam agents which require 10-14 days. 1
• Do not fail to adjust therapy based on culture results once susceptibility data becomes available. 1, 2

Monitoring and Follow-Up

• Repeat urine culture 1-2 weeks after completion of antibiotic therapy to confirm eradication. 5
• If the patient fails to improve within 48-72 hours, obtain imaging (preferably CT scan) to evaluate for complications such as renal abscess or obstruction. 2
• Lack of response should prompt repeat blood and urine cultures and consideration of resistant organisms or anatomic abnormalities. 5