What is the recommended treatment for pyelonephritis?

Treatment of Pyelonephritis

Outpatient Management

For outpatient treatment of pyelonephritis, oral fluoroquinolones (ciprofloxacin 500 mg twice daily for 7 days or levofloxacin 750 mg daily for 5 days) are first-line therapy when local fluoroquinolone resistance is below 10%. 1

Pre-Treatment Requirements

• Always obtain urine culture and susceptibility testing before initiating antibiotics to guide definitive therapy and avoid treatment failure 1
• This is the single most critical step that is frequently missed in clinical practice 1

Fluoroquinolone Regimens (When Local Resistance <10%)

• Ciprofloxacin 500 mg orally twice daily for 7 days 1
• Ciprofloxacin 1000 mg extended-release orally once daily for 7 days 1
• Levofloxacin 750 mg orally once daily for 5 days 1, 2
• The 5-day levofloxacin regimen demonstrated equivalent efficacy to 10-day ciprofloxacin in clinical trials 2

Modified Approach When Fluoroquinolone Resistance ≥10%

If local fluoroquinolone resistance exceeds 10%, you must administer one dose of a long-acting parenteral antibiotic (ceftriaxone 1g IV or an aminoglycoside) before starting oral fluoroquinolone therapy 1

• This single parenteral dose significantly improves outcomes when resistance rates are elevated 1
• Do not use fluoroquinolones empirically without this initial parenteral dose in high-resistance areas 1

Alternative Oral Regimens

• Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg (double-strength) twice daily for 14 days is appropriate only if the pathogen is documented as susceptible 1
• TMP-SMX should not be used empirically due to high resistance rates in most communities 3, 4
• Oral β-lactams should not be used as monotherapy without an initial parenteral dose due to inferior efficacy 1

Inpatient Management

Hospitalized patients require initial intravenous therapy with fluoroquinolones, aminoglycosides (with or without ampicillin), extended-spectrum cephalosporins/penicillins (with or without aminoglycosides), or carbapenems, selected based on local resistance patterns 1

Indications for Hospitalization

• Severe illness or sepsis 1, 4
• Inability to tolerate oral medications (persistent vomiting) 4
• Suspected complications (obstruction, abscess) 1
• Failed outpatient therapy 4
• Extremes of age or immunocompromised state 1, 4

Intravenous Antibiotic Options

• Fluoroquinolones (levofloxacin 750 mg IV daily) 1, 2
• Aminoglycosides (gentamicin 5-7 mg/kg once daily) with or without ampicillin 1
• Extended-spectrum cephalosporins (ceftriaxone 1g IV every 12-24 hours) 1, 5
• Extended-spectrum penicillins with or without aminoglycosides 1
• Carbapenems for suspected multidrug-resistant organisms 1

Transition to Oral Therapy

• Switch to oral antibiotics once the patient is clinically improving and able to tolerate oral intake 1
• Adjust therapy based on culture and susceptibility results 1

Treatment Duration

Treatment duration varies by antibiotic class and must be followed precisely to prevent treatment failure:

• Fluoroquinolones: 5-7 days depending on the specific agent 1
• TMP-SMX: 14 days (traditional recommendation) 1
• β-lactams: 10-14 days (longer duration required due to lower efficacy) 1

Microbiology

• Escherichia coli causes 75-95% of pyelonephritis cases 1
• Other common pathogens include Proteus mirabilis and Klebsiella pneumoniae 1
• Resistance patterns are rapidly evolving, with increasing fluoroquinolone resistance (10-18% in community settings, higher in hospitals) 6

Special Populations

• Elderly patients require close monitoring for adverse effects, particularly with aminoglycosides and fluoroquinolones 1
• Pregnant patients should be hospitalized and treated with parenteral therapy due to elevated risk of severe complications 7

Follow-Up and Treatment Failure

• Most patients respond within 48-72 hours of appropriate antibiotic therapy 7
• Lack of response warrants repeat cultures, imaging (contrast-enhanced CT), and consideration of alternative diagnoses 1, 7
• Urine culture should be repeated 1-2 weeks after completion of therapy to document cure 4

Critical Pitfalls to Avoid

• Failing to obtain urine cultures before antibiotics is the most common error 1
• Not considering local resistance patterns when selecting empiric therapy 1
• Using fluoroquinolones empirically in areas with >10% resistance without an initial parenteral dose 1
• Using oral β-lactams as monotherapy without initial parenteral therapy 1
• Not adjusting therapy based on culture results 1
• Inadequate treatment duration, especially with β-lactam agents 1