Metronidazole

Oral health effects

• Metallic taste (dysgeusia)

  A common, characteristic side effect.

  Clinical management: Reassure; usually resolves after the course.

• Disulfiram-like reaction with alcohol

  Combining with alcohol can cause flushing, nausea, and vomiting.

  Clinical management: Advise avoiding alcohol during and shortly after the course, relevant for periodontal infections.

• Antibiotic-associated diarrhea / gut dysbiosis

  Disrupts flora; can promote diarrhea and Candida overgrowth.

  Clinical management: A probiotic (e.g., Saccharomyces boulardii) during the course may modestly lower the risk of antibiotic-associated diarrhea; the evidence is low certainty. Avoid probiotics in immunocompromised or severely ill patients. See the Gut Health page.

• Furry tongue, glossitis and stomatitis

  Furry tongue, glossitis and stomatitis have occurred and may be linked to a sudden overgrowth of Candida during therapy. Frequency not stated.

  Clinical management: Examine the tongue and mucosa for candidiasis and refer for antifungal therapy if present. Teach tongue brushing. Bland rinses for soreness, and avoid alcohol-containing mouthwashes during therapy and for 3 days afterwards (disulfiram-like reaction).

• Dry mouth (xerostomia)

  Dryness of the mouth is a listed adverse reaction. Frequency not stated. It is usually short-lived because metronidazole courses are short.

  Clinical management: Advise frequent sips of water, sugar-free xylitol gum or lozenges, and alcohol-free saliva substitutes. Avoid alcohol-containing mouth rinses during therapy.