Metronidazole

Summary

Metronidazole is an antibiotic used to treat bacterial infections, including clostridium difficile and trichomoniasis. When taken concurrently with alcohol, it can cause a disulfiram-like reaction so patients should avoid alcohol while taking the drug. Metronidazole can cause a host of harmless side effects, including metallic taste in the mouth and reddish-brown urine discoloration. Both of these side effects are expected and benign, so patients should be consoled to not worry about them when they occur.

Key Points

• Metronidazole (Flagyl)
  • Mechanism
    • Antibiotic
      • Creates free radicals that damage bacterial DNA, causing cell death
  • Clinical Use
    • Gastrointestinal infections
      • C. difficile
        • First-line treatment
      • H. pylori
        • Associated with peptic and duodenal ulcers
      • Giardiasis
      • Amoebiasis
    • Gynecological infections
      • Trichomoniasis
        • Sexually-transmitted infection characterized by grey frothy vaginal discharge with a fishy odor
        • Partners should also be treated
      • Bacterial vaginosis
    • Prophylaxis for surgical infections
    • Acne rosacea
    • Anaerobic bacterial infections
  • SE and AR
    • (Disulfiram-Like) Reaction to alcohol
      • Flushing, headache, visual disturbance, confusion, dyspnea, nausea, vomiting
      • Alcohol should be avoided until at least 48 hours after treatment is completed
    • Metallic taste
      • This is an expected side effect, no need to report
    • Red/brown urine discoloration
      • This is an expected side effect, no need to report
    • Stevens-Johnson Syndrome
      • Immediately report any skin rash or peeling
      • Can be fatal if not treated
    • Peripheral neuropathy
      • Can appear with long-term use