Fluoroquinolone Prophylaxis during Conventional Chemotherapy or Hematopoietic Stem Cell Transplantation for Acute Leukemia-Pros and Cons

Background: Prophylaxis with fluoroquinolones (FQ) is commonly used in patients with acute leukemia (AL) during neutropenia. This practice is supported by an older meta-analysis reporting reduced mortality using FQ prophylaxis. Later meta-analyses have failed to reproduce this finding, presumably due to higher background FQ resistance rates limiting their effectiveness. Summary: This article reviews the pros and cons of FQ prophylaxis mainly in patients with AL. Most current guidelines do not support universal prophylaxis but rather recommend a selective approach, weighing the benefits against the risks. This recommendation is based on the lack of mortality benefit reported in more recent meta-analyses. FQ prophylaxis was demonstrated to reduce bacteremia and febrile neutropenia episodes, although mostly in trials performed in low-resistance settings (<20%), whereas current FQ resistance rates may reach 30-60%. Other disadvantages of FQ include potential adverse events, antibiotic resistance development, cost, increase in Gram-positive infections and resistant Gram-negative infections following prophylaxis, Clostridioides difficile infection, and an effect on gut microbiota. Key Messages: Taking the above into consideration, alternative approaches other than universal FQ prophylaxis should be considered. Centers with high FQ resistance rates may consider either withholding prophylaxis or providing selective prophylaxis for high-risk patients screened negative for FQ-resistant bacteria.