Fluoroquinolones

Snapshot

  • A 44-year-old man presents to the emergency department for intractable seizures. He was sedated, intubated, and admitted to the intensive care unit. He remained intubated and on a ventilator due to difficulty weaning sedation in the setting of recurring seizures. After a few days of admission, he developed a fever and an increase in oxygen requirement. A chest radiograph demonstrated a new lung infiltrate and leukocytosis was noted on a complete blood count. He has never been hospitalized in the past and was otherwise healthy. Blood and respiratory cultures are obtained and he is started on intravenous levofloxacin. (Ventilator-associated pneumonia)

Introduction

  • Mechanism of action
    • a prokaryotic topoisomerase II (DNA gyrase) and IV inhibitor, which directly inhibits DNA synthesis
  • Mechanism of resistance
    • altered DNA gyrase and topoisomerase IV
    • synthesis of membrane efflux pumps
  • Clinical use
    • gram-negative rods (in the urinary and gastrointestinal tracts)
    • otitis externa
  • Adverse effects
    • gastrointestinal upset
    • tendonitis or tendon rupture 
    • QT prolongation
    • contraindicated in pregnancy, nursing mothers, and < 18 years of age
      • secondary to possible cartilage damage