Clinical decision-support only. For use by licensed dental professionals. Not a substitute for professional judgment or a complete drug reference. Always verify with primary sources.
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Medication

Phenytoin

Anticonvulsant (hydantoin)

Brand names: Dilantin, Phenytek

Oral health effects

  • Gingival overgrowth (gingival hyperplasia)

    Classic and common cause of drug-induced gingival enlargement, often beginning at the interdental papillae within 1–3 months. Reported in roughly 50% of users.

    Mechanism: Phenytoin promotes fibroblast proliferation and collagen accumulation; plaque-driven inflammation amplifies the response.

    Clinical management: Meticulous plaque control reduces severity. Reinforce oral hygiene, increase recall frequency, refer for gingivectomy if function/aesthetics are affected, and liaise with the prescriber about alternatives.

  • Severe mucocutaneous reactions (SJS/TEN)

    Phenytoin can cause Stevens-Johnson syndrome or toxic epidermal necrolysis with painful oral ulceration (label warning); risk is higher in carriers of HLA-B*15:02 (mainly people of Asian ancestry).

    Clinical management: Ask about new rash, fever or mouth ulcers, especially in the first two months of therapy. Painful erosions of the lips and mouth with skin rash are a medical emergency: refer urgently to the physician and do not delay for dental treatment.

  • Metallic taste (dysgeusia)

    The label lists altered taste sensation, including metallic taste.

    Clinical management: Ask about altered or metallic taste, which can reduce appetite and oral comfort; reassure that it is drug-related and often fades. Rule out oral candidiasis or poor hygiene as contributors and encourage sugar-free options rather than sweet foods/drinks used to mask the taste.

Sources

  1. Mechanism of drug-induced gingival overgrowth revisited: a unifying hypothesis. Brown RS, Arany PR. Oral diseases, 2015.
  2. Drug-Induced Gingival Overgrowth-Molecular Aspects of Drug Actions. Droździk A, Droździk M. International journal of molecular sciences, 2023.
  3. Phenytoin prescribing information (FDA label) Mylan Pharmaceuticals Inc. / DailyMed, 2024.
  4. Unraveling the genetic link: an umbrella review on HLA-B*15:02 and antiepileptic drug-induced Stevens-Johnson syndrome/toxic epidermal necrolysis. Tham KM, Yek JJL, Liu CWY. Pharmacogenetics and genomics, 2024.
  5. A review and guide to drug-associated oral adverse effects-Oral mucosal and lichenoid reactions. Part 2. Teoh L, Moses G, McCullough MJ. Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology, 2019.