What is the best antibiotic for pyelonephritis (infection of the kidney)?

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Last updated: May 21, 2025View editorial policy

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From the Guidelines

For uncomplicated pyelonephritis, levofloxacin (750 mg orally once daily for 5 days) is the recommended first-line therapy, as suggested by the most recent guidelines from the European Association of Urology 1. This recommendation is based on the latest evidence, which prioritizes the use of fluoroquinolones, such as levofloxacin, due to their efficacy and safety profile. The choice of antibiotic should always consider local resistance patterns and be adjusted based on urine culture results. Some key points to consider when treating pyelonephritis include:

  • The use of fluoroquinolones, such as ciprofloxacin (500–750 mg twice daily for 7 days) or levofloxacin (750 mg once daily for 5 days), as first-line therapy 1.
  • The importance of considering local resistance patterns and adjusting treatment accordingly 1.
  • The need for adequate hydration and follow-up urine cultures to confirm clearance of infection.
  • The consideration of alternative antibiotics, such as trimethoprim-sulfamethoxazole (160/800 mg twice daily for 14 days) or third-generation cephalosporins, such as ceftriaxone (1-2g IV daily), in cases where fluoroquinolones are not suitable 1.

From the Research

Treatment Options for Pyelonephritis

  • The choice of antibiotic for treating pyelonephritis depends on various factors, including the severity of the infection, patient's medical history, and local resistance patterns 2, 3, 4, 5, 6.
  • Cephalosporins, such as ceftriaxone, have been shown to be effective in treating pyelonephritis, with a higher microbiological response rate compared to levofloxacin 2.
  • Fluoroquinolones, such as levofloxacin, are also commonly used to treat pyelonephritis, but their effectiveness may be limited by high resistance rates in some areas 4, 5.
  • Oral cephalosporins have been compared to first-line agents, such as fluoroquinolones and trimethoprim/sulfamethoxazole, in the treatment of acute pyelonephritis, with no significant difference in urinary tract infection recurrence rates found between the two groups 6.

Antibiotic Resistance

  • High resistance rates have been detected for commonly used antibiotics, such as cotrimoxazole, ciprofloxacin, and ceftriaxone, in patients with pyelonephritis 2, 3.
  • The emergence of widespread fluoroquinolone resistance has prompted a re-examination of the use of levofloxacin in the treatment of urinary tract infections, including pyelonephritis 4.
  • Efforts to promote fluoroquinolone-sparing agents and to use antibiotics in compliance with antimicrobial guidelines are recommended to decrease the spread of antibiotic resistance 4.

Clinical Outcomes

  • Clinical outcomes, such as cure rates and failure rates, have been compared between different antibiotic regimens in the treatment of pyelonephritis 2, 3, 6.
  • The choice of antibiotic regimen may depend on the severity of the infection, patient's medical history, and local resistance patterns, with the goal of achieving the best possible clinical outcome while minimizing the risk of antibiotic resistance 2, 3, 4, 5, 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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