Phenytoin

Phenytoin sodium (marketed as "Dilantin" by Parke-Davis, now part of Pfizer) was approved by the Food and Drug Administration in 1953 as an anti-convulsant.

Phenytoin (diphenylhydantoin) was first synthesized by a German physician named Heinrich Biltz in 1908. Biltz sold his discovery to Parke-Davis, which did not find an immediate use for it. In 1938, outside doctors discovered phenytoin's usefulness for controlling seizures, without the sedation effects associated with phenobarbital. There are some indications that phenytoin has other effects, including anxiety control and mood stabilization, although it has never been approved for those purposes by the FDA.

Jack Dreyfus, founder of the Dreyfus Fund, became a major proponent of phenytoin as a means to control nervousness and depression when he received a prescription for Dilantin in 1966. Despite more than $70 million in personal financing, his push to see phenytoin evaluated for alternative uses has had little lasting effect on the medical community. This was partially due to Parke-Davis's reluctance to invest in a drug nearing the end of its patent life, and partially due to mixed results from various studies.

There is some evidence that phenytoin can be teratogenic, and that it may accumulate in the cerebral cortex over long periods of time. Despite this, the drug has a long history of safe use, making it one of the more popular anti-convulsants prescribed by doctors, and a common "first line of defense" in seizure cases. Due to patent expiration, phenytoin is available in generic form at relatively low cost, making it one of the more affordable seizure control medications. It is available in extended release capsules and injectable forms.

In 1995, Warner-Lambert, then producer of Dilantin, was fined $10 million after pleading guilty to charges that it hid quality control failures from regulators during the period 1990-1992.