PHENYTOIN SODIUM capsule extended release

País: Estados Unidos

Língua: inglês

Origem: NLM (National Library of Medicine)

Ingredientes ativos:

PHENYTOIN SODIUM (UNII: 4182431BJH) (PHENYTOIN - UNII:6158TKW0C5)

Disponível em:

Upsher-Smith Laboratories, Inc.

DCI (Denominação Comum Internacional):

PHENYTOIN SODIUM

Composição:

PHENYTOIN SODIUM 100 mg

Tipo de prescrição:

PRESCRIPTION DRUG

Status de autorização:

Abbreviated New Drug Application

Características técnicas

PHENYTOIN SODIUM- PHENYTOIN SODIUM CAPSULE, EXTENDED RELEASE
UPSHER-SMITH LABORATORIES, INC.
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EXTENDED PHENYTOIN SODIUM CAPSULES USP, 100 MG
RX ONLY
DESCRIPTION
Phenytoin sodium is an antiepileptic drug. Phenytoin sodium is related
to the barbiturates in chemical
structure, but has a five-membered ring. The chemical name is sodium
5,5-diphenyl-2,4-
imidazolidinedione, having the following structural formula:
Each Extended Phenytoin Sodium Capsule, USP contains 100 mg phenytoin
sodium, USP. Also contains
confectioner's sugar, hypromellose, lactose monohydrate, magnesium
stearate, and talc. The capsule
shell contains benzyl alcohol, black ink, butylparaben, D&C Yellow
#10, edetate calcium disodium,
FD&C Red #3, gelatin, methylparaben, propylparaben, sodium lauryl
sulfate, sodium propionate, and
titanium dioxide. Product _in vivo_ performance is characterized by a
slow and extended rate of absorption
with peak blood concentrations expected in 4 to 12 hours as contrasted
to _Prompt Phenytoin Sodium_
_Capsules_, USP with a rapid rate of absorption with peak blood
concentration expected in 1½ to 3 hours.
CLINICAL PHARMACOLOGY
MECHANISM OF ACTION
Phenytoin is an antiepileptic drug which can be useful in the
treatment of epilepsy. The primary site of
action appears to be the _motor cortex_ where spread of seizure
activity is inhibited. Possibly by
promoting sodium efflux from neurons, phenytoin tends to _stabilize_
the threshold against
hyperexcitability caused by excessive stimulation or environmental
changes capable of reducing
membrane sodium gradient. This includes the reduction of post tetanic
potentiation at synapses. Loss of
post tetanic potentiation prevents cortical seizure foci from
detonating adjacent cortical areas. Phenytoin
reduces the maximal activity of brain stem centers responsible for the
tonic phase of tonic-clonic (grand
mal) seizures.
PHARMACOKINETICS AND DRUG METABOLISM
The plasma half-life in man after oral administration of phenytoin
averages 22 hours, with a range of 7
to 42 hours. St