Amoxicillin

Oral health effects

• Oral candidiasis (thrush)

  Broad-spectrum antibiotics suppress commensal bacteria, allowing Candida overgrowth in the mouth.

  Mechanism: Loss of competitive inhibition from normal flora.

  Clinical management: Watch for thrush, especially with repeated courses; treat with an antifungal; reinforce hygiene.

• Antibiotic-associated diarrhea / gut dysbiosis

  Disruption of gut flora can cause diarrhea and C. difficile 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.

• Black hairy tongue (lingua villosa nigra)

  Elongated, darkly stained filiform papillae on the dorsal tongue, linked to antibiotic-related shifts in oral flora. Listed in postmarketing reports; frequency not established.

  Clinical management: Reassure the patient that it is benign and reversible. Teach daily tongue brushing or scraping and good oral hygiene; it usually resolves after the course ends. Distinguish from candidiasis or pigmented lesions.