Side effects of diphenylhydantoin: a review.

For almost 40 years, diphenylhydantoin has been the preferred drug in the treatment of seizure disorders. Soon after the drug was introduced into clinical practice, gingival enlargement was noticed as a side effect and, despite much research effort, the etiology of this condition remains unknown. More recently, diphenylhydantoin-induced osteomalacia and the teratogenic effects of the drug have been reported. Recent advances in our knowledge of these conditions will be discussed and future directions for research will be outlined.