Gingival Overgrowth as a Side Effect of Dilantin (Phenytoin)

Certain medications used to control seizures may cause an oral condition known as gingival enlargement (also known as gingival overgrowth or gingival hyperplasia), increasing the risk of periodontal disease, tooth decay, and oral infections.

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Gingival Overgrowth and Enlargement

Dilantin (phenytoin) is an antiepileptic drug used to control seizures in certain types of epilepsy. It is also used to prevent seizures during or after brain surgery. As with most medications, side effects are associated with the use of phenytoin.

Considered a common side effect associated with Dilantin use, signs of gingival overgrowth and enlargement usually begin to appear one to three months after the introduction of the medication and tend only to involve the gum tissue that is firmly attached to the teeth and bone; known as attached gingiva. Patients experiencing gingival overgrowth may experience the following:

  • Enlargement of the interdental papilla especially in the front (anterior) of the mouth
  • As the tissue begins to enlarge, it may become denser (fibrotic)
  • Inflammation in areas of enlarged tissue may start to interrupt speech, eating, and esthetics
  • Painful regions of the mouth, bleeding gums, tooth movement, and changes in how the teeth bite together (occlusion) are common
  • Enlarged gingival tissue may begin to impose on the crown of the tooth. This causes the patient difficulty when trying to brush and floss the teeth thoroughly
  • Tooth decay and periodontal disease may become more prevalent due to the interference of the excessive gum tissue


Patients who are experiencing drug-associated gingival enlargement are treated according to the extent of the overgrowth of tissue. Your dentist may recommend treatments such as:

  • Regularly scheduled hygiene appointments, as frequently as every three months, to ensure the thorough removal of plaque and calculus in the area that is inaccessible with a toothbrush and floss
  • A mouth rinse containing chlorhexidine as an aid in reducing the enlargement of tissue
  • A change in brushing technique to allow for the slight recession of the gum tissue from the toothbrush
  • Surgical removal of the excessive tissue known as a gingivectomy
  • Antifungal medication and/or antibiotics, depending on the severity of the overgrowth
  • Changes in medication, although this will depend on the individual situation of each patient

Patients with gingival enlargement will most likely be referred to see a periodontist—a dentist specializing in diagnosing, preventing, and treating gum disease.

Your Best Defense

Although patients may not be able to control the overgrowth of their gum tissue directly, the best way to help eliminate uncomfortable side effects is to pay close attention to plaque removal. It may be wise to consider brushing and flossing after every meal and to significantly reduce or eliminate unnecessary sugars and carbohydrates in the diet.

Book regular dental visits and follow the recommended frequency for professional cleanings as suggested by your dentist or dental hygienist. Discuss alternative medications and treatments with your healthcare provider and never discontinue your prescribed medication without consulting your healthcare provider.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Candotto V, Pezzetti F, Baj A, et al. Phenytoin and gingival mucosa: a molecular investigation. Int J Immunopathol Pharmacol. 2019;33:205873841982825. doi:10.1177/2058738419828259

  2. Zoheir N, Hughes FJ. The management of drug-influenced gingival enlargement. Prim Dent J. 2020;8(4):34-39. doi:10.1308/205016820828463816

By Shawn Watson
Shawn Watson is an orthodontic dental assistant and writer with over 10 years of experience working in the field of dentistry.