Medicine & USMLE


Anti-Infective Drugs
  1. Vancomycin
  2. Metronidazole
  3. Penicillins
  4. Cephalosporins
  5. Macrolides
  6. Fluoroquinolones
  7. Aminoglycosides
  8. Tetracyclines
  9. Sulfonamides
  10. Rifampin
  11. Isoniazid
  12. Ethambutol
  13. Chloroquine
  14. Acyclovir
  15. Oseltamivir
  16. Azoles
  17. Nystatin
  18. Amphotericin B


Fluoroquinolones are antibacterial drugs recognizable by their common “-floxacin” ending, like ciprofloxacin or levofloxacin. These drugs are antibiotics used to treat a wide variety of bacterial infections. The most severe adverse reaction of fluoroquinolones is tendon rupture, so patients should be educated to stop taking the medication and notify a provider at the first sign of tendon pain. Fluoroquinolones should not be taken with iron, calcium, or antacids. It’s also important to note that fluoroquinolones can cause several drug interactions, especially with warfarin or theophylline. Fluoroquinolones can cause photosensitivity or easy sunburning, so patients should be taught to wear sunblock and avoid direct sunlight.

Key Points

  • Fluoroquinolones
    • Key Drugs (-floxacin ending)
      • Ciprofloxacin
      • Levofloxacin
      • Moxifloxacin
      • Norfloxacin
      • Ofloxacin
    • Mechanism
      • Antibiotic
        • Inhibits DNA gyrase, which is necessary for bacteria synthesis
        • Bactericidal
        • Treats both gram positive and gram negative
    • Clinical Use
      • Bacterial infections
        • Urinary tract infections
        • E. Coli
        • Bronchitis
        • Pneumonia
        • Gonorrhea
      • Anthrax prophylaxis
    • Side Effects and Adverse Reactions
      • Tendon rupture / Tendonitis
        • Black box warning
        • Most commonly in the achilles tendon
        • At the first sign of tendon pain, the patient should stop taking the mediation and notify provider
      • Do not take with antacids, dairy products (calcium), or iron
        • These drugs can bind the drug in the GI tract, preventing absorption and making treatment ineffective
      • Photosensitivity
        • Use of fluoroquinolones may lead to photosensitivity and easy sunburning; patients should be counseled to use sunscreen and stay indoors if possible
      • Drug interactions (ciprofloxacin)
        • Ciprofloxacin inhibits CYP450 enzymes and can increase levels of other drugs like theophylline and warfarin
      • Altered blood glucose
        • Fluoroquinolones can cause hyper- or hypoglycemia, especially in older patients
      • Yeast infection (candidiasis)
        • Due to elimination of existing oral or vaginal flora, opening space for candida overgrowth
      • Peripheral neuropathy