What are the recommended antibiotics for pyelonephritis?

Recommended Antibiotics for Pyelonephritis

Ciprofloxacin is the first-choice antibiotic for pyelonephritis in adults when local antimicrobial resistance patterns allow, with a recommended dosage of 500 mg twice daily for 7 days. 1

First-Line Treatment Options

For adults with pyelonephritis, the recommended treatment options include:

• Fluoroquinolones:

  • Ciprofloxacin 500 mg orally twice daily for 7 days 1, 2
  • For severe/complicated cases: Ciprofloxacin 750 mg orally twice daily for 7-14 days 3
  • Initial IV therapy may be appropriate for severe cases, with conversion to oral therapy when clinically improved 3

• Alternative options (when fluoroquinolones cannot be used or resistance is suspected):

  • Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg twice daily for 14 days (only if local resistance is <20%) 1, 4
  • Third-generation cephalosporins (e.g., ceftriaxone) 5, 6

Treatment Duration

• 7 days of ciprofloxacin has been shown to be as effective as 14 days for acute uncomplicated pyelonephritis in women 2
• Ciprofloxacin for 7 days has demonstrated superior bacteriologic and clinical cure rates compared to TMP-SMX for 14 days (99% vs 89% bacteriologic cure) 4

Special Considerations

Renal Impairment

Dosage adjustments are necessary for patients with renal impairment 1, 3:

Creatinine Clearance	Recommended Ciprofloxacin Dosing
>50 mL/min	Standard dosing
30-50 mL/min	250-500 mg every 12 hours
5-29 mL/min	250-500 mg every 18 hours
Hemodialysis/Peritoneal dialysis	250-500 mg every 24 hours (after dialysis)

Pediatric Patients

For pediatric patients with pyelonephritis 1, 3:

• Intravenous: 6-10 mg/kg (maximum 400 mg per dose) every 8 hours
• Oral: 10-20 mg/kg (maximum 750 mg per dose) every 12 hours
• Total duration: 10-21 days

Important: Fluoroquinolones should be avoided in children and adolescents except in special circumstances due to the risk of fluoroquinolone-associated tendinopathy 1

Antimicrobial Resistance Considerations

• Local resistance patterns should guide empiric therapy choices 1, 6
• E. coli resistance to TMP-SMX can be as high as 18%, while resistance to ciprofloxacin is generally lower 4
• In areas with high fluoroquinolone resistance (>10%), consider initial therapy with a parenteral third-generation cephalosporin 6

Monitoring and Follow-up

• No routine post-treatment urinalysis or urine cultures are indicated for asymptomatic patients 1
• No routine laboratory monitoring is required for short-course therapy 1
• Drug levels should be monitored for antibiotics with narrow therapeutic windows (e.g., aminoglycosides) 1

Common Pitfalls to Avoid

• Using fluoroquinolones in patients with recent fluoroquinolone exposure (increased resistance risk) 6
• Failing to adjust dosage in patients with renal impairment 1, 3
• Using broader-spectrum antibiotics than necessary, which contributes to antimicrobial resistance 6
• Continuing empiric therapy without adjusting based on culture and sensitivity results 6

The evidence strongly supports ciprofloxacin as first-line therapy for pyelonephritis in adults, with appropriate alternatives based on patient factors and local resistance patterns.