Phenytoin
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Missing image | |
| 5,5-diphenyl-2,4- imidazolidinedione | |
| CAS number 57-41-0 | ATC code N03AB02 |
| Chemical formula | C15H12N2O2 |
| Molecular weight | 252.272 |
| Bioavailability | ? |
| Metabolism | ? |
| Elimination half-life | ? |
| Excretion | ? |
| Pregnancy category | ? |
| Legal status | ? |
| Routes of administration | Oral, intravenous |
Phenytoin sodium (marketed as Dilantin® in the USA and as Epanutin® in the UK, by Parke-Davis, now part of Pfizer) is a commonly used antiepileptic. It was approved by the Food and Drug Administration in 1953 for use in seizures.
History
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 scientists 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. Richard Nixon was one of the patients to who Dreyfus prescribed Dilantin.
Side-effects
There is some evidence that phenytoin can be teratogenic, and that it may accumulate in the cerebral cortex over long periods of time, as well as causing atrophy of the cerebellum in chronically high levels. 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. Phenytoin may also cause gingival hyperplasia.
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.
Legal issues
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.pt:Fenitoína