Dilantin

Phenytoin

Clinical data
Pronunciation	/fəˈnɪtoʊᵻn/; /ˈfɛnᵻtɔɪn/
Trade names	Originally Dilantin, many names worldwide
AHFS/Drugs.com	Monograph
MedlinePlus	a682022
Pregnancy category	AU: D US: D (Evidence of risk)
Routes of administration	Oral,
ATC code	N03AB02 (WHO)
Legal status
Legal status	AU: S4 (Prescription only) CA: ℞-only UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Bioavailability	70–100% oral, 24.4% for rectal administration
Protein binding	95%
Metabolism	liver
Onset of action	10 to 30 min (IV)
Biological half-life	10–22 hours
Duration of action	24 hr
Excretion	Primarily through the bile, urinary
Identifiers
IUPAC name 5,5-diphenylimidazolidine-2,4-dione
CAS Number	57-41-0 Y
PubChem CID	1775
IUPHAR/BPS	2624
DrugBank	DB00252 Y
ChemSpider	1710 Y
UNII	6158TKW0C5
KEGG	D00512 Y
ChEBI	CHEBI:8107 N
ChEMBL	CHEMBL16 N
ECHA InfoCard	100.000.298
Chemical and physical data
Formula	C15H12N2O2
Molar mass	252.268 g/mol
3D model (Jmol)	Interactive image
SMILES O=C2NC(=O)NC2(c1ccccc1)c3ccccc3
InChI InChI=1S/C15H12N2O2/c18-13-15(17-14(19)16-13,11-7-3-1-4-8-11)12-9-5-2-6-10-12/h1-10H,(H2,16,17,18,19) N Key:CXOFVDLJLONNDW-UHFFFAOYSA-N N
NY (what is this?)

Phenytoin, sold under the brand name Dilantin among others, is an anti-seizure medication. It is useful for the prevention of tonic-clonic seizures, partial seizures, but not absence seizures. The intravenous form is used for status epilepticus that does not improve with benzodiazepines. It may also be used for certain heart arrhythmias or neuropathic pain. It can be taken intravenously or by mouth. The intravenous form generally begins working within 30 minutes and is effective for 24 hours. Blood levels can be measured to determine the proper dose.

Common side effects include nausea, stomach pain, loss of appetite, poor coordination, increased hair growth, and enlargement of the gums. Potentially serious side effects include sleepiness, self harm, liver problems, bone marrow suppression, low blood pressure, and toxic epidermal necrolysis. There is evidence that use during pregnancy results in abnormalities in the baby. It appears to be safe to use when breastfeeding. Alcohol may interfere with the medication's effects.

Phenytoin was first made in 1908 by the German chemist Heinrich Biltz and found useful for seizures in 1936. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Phenytoin is available as a generic medication and usually not too expensive. The wholesale cost in the developing world is between US$0.003 and US$0.15 per dose. A month of treatment is about US$30 in the United States.