Which antiseizure medication is most associated with gingival hyperplasia and hirsutism?

• A. Lamotrigine
• B. Valproate
• C. Phenytoin
• D. Carbamazepine

Answer: (C)

Gingival hyperplasia and hirsutism are classic adverse effects associated with phenytoin. Phenytoin can cause gingival tissue to proliferate and produce excess extracellular matrix by stimulating gingival fibroblasts and reducing collagenase activity, especially in the presence of dental plaque and inflammation. This leads to thickened, overgrown gums. Hirsutism from phenytoin is a well-known dose-related effect, likely related to hormonal or metabolic changes the drug induces, though the exact mechanism isn’t fully understood. Among the listed antiseizure medications, this combination of gingival overgrowth and increased body hair is most characteristically linked to phenytoin, whereas the other agents have different predominant adverse effect profiles (for example, rashes with lamotrigine, hepatotoxicity or weight changes with valproate, hyponatremia or hematologic effects with carbamazepine).