PHENYTOIN (diphenylhydantoin) is a clinically accepted therapeutic agent for seizure control, for the treatment of cardiac arrhythmias, and in the diagnosis (and treatment) of certain endocrine diseases. In addition, however, phenytoin has been reported to be of value in treating at least 75 different symptoms and disorders. Bogoch and Dreyfus1 have reported these various clinical uses in their book, The Broad Range of Use of Diphenylhydantoin. As pointed out in the Medical Letter on Drugs and Therapeutics, the book lists a total of 75 symptoms and disorders, from abdominal pain to wounds, in which phenytoin is reported to be valuable. The bibliography is of interest, but the reviews of the uses of the drug are too uncritical to be of much value. Of the 750 articles mentioned, only 17 studies are described as being controlled to any extent.
The majority of these proposed uses are supported only by anecdotal evidence.
Walson P, Trinca C, Bressler R. New Uses for Phenytoin. JAMA. 1975;233(13):1385–1389. doi:10.1001/jama.1975.03260130043024