Mephenytoin

Mephenytoin Uses, Dosage, Side Effects, Food Interaction and all others data.

Mephenytoin is used for the treatment of refractory partial epilepsy. Mephenytoin is a solid. This compound belongs to the phenylhydantoins. These are heterocyclic aromatic compounds containing an imiazolidinedione moiety substituted by a phenyl group. Mephenytoin is known to target sodium channel protein type 5 subunit alpha. Cytochrome P450 2C19, Cytochrome P450 2C8, Cytochrome P450 2C9, Cytochrome P450 2B6, Cytochrome P450 1A2, and Cytochrome P450 2D6 are known to metabolize mephenytoin. Mephenytoin is a hydantoin-derivative anticonvulsant used to control various partial seizures. Mephenytoin and oxazolidinedione derivatives are associated with higher incidences of blood dyscrasias compared to other anticonvulsants.

Mephenytoin 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, mephenytoin 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 posttetanic potentiation at synapses. Loss of posttetanic potentiation prevents cortical seizure foci from detonating adjacent cortical areas. Mephenytoin reduces the maximal activity of brain stem centers responsible for the tonic phase of tonic-clonic (grand mal) seizures.

Mephenytoin
Uses
Dosage
Side Effect
Precautions
Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
Half Life
Volume of Distribution
Clearance
Interaction With other Medicine
Contradiction
Storage

Trade Name	Mephenytoin
Availability	Discontinued
Generic	Mephenytoin
Mephenytoin Other Names	mefenitoína, Mephenytoin
Type
Formula	C₁₂H₁₄N₂O₂
Weight	Average: 218.2518 Monoisotopic: 218.105527702
Groups	Approved, Investigational, Withdrawn
Therapeutic Class
Manufacturer
Available Country
Last Updated:	September 19, 2023 at 7:00 am

Uses

Mephenytoin is a phenylhydantoin used to treat refractory partial epilepsy.

For the treatment of refractory partial epilepsy.

How Mephenytoin works

The mechanism of action of mephenytoin is not definitely known, but extensive research strongly suggests that its main mechanism is to block frequency-, use- and voltage-dependent neuronal sodium channels, and therefore limit repetitive firing of action potentials.

Food Interaction

[Moderate] ADJUST DOSING INTERVAL: Phenytoin bioavailability may decrease to subtherapeutic levels when the suspension is given concomitantly with enteral feedings.

The mechanism may be related to phenytoin binding to substances in the enteral formula (e.g., calcium, protein) and

Data have been conflicting and some studies have reported no changes in phenytoin levels, while others have reported significant reductions.

MONITOR: Acute consumption of alcohol may increase plasma phenytoin levels.

Chronic consumption of alcohol may decrease plasma phenytoin levels.

The mechanism of this interaction is related to induction of phenytoin metabolism by ethanol during chronic administration.

Other hydantoin derivatives may be similarly affected by ethanol.

MANAGEMENT: Some experts have recommended interrupting the feeding for 2 hours before and after the phenytoin dose, giving the phenytoin suspension diluted in water, and flushing the tube with water after administration; however, this method may not entirely avoid the interaction and is not always clinically feasible.

Patients should be closely monitored for clinical and laboratory evidence of altered phenytoin efficacy and levels upon initiation and discontinuation of enteral feedings.

Dosage adjustments or intravenous administration may be required until therapeutic serum levels are obtained.

In addition, patients receiving phenytoin therapy should be warned about the interaction between phenytoin and ethanol and they should be advised to notify their physician if they experience worsening of seizure control or symptoms of toxicity, including drowsiness, visual disturbances, change in mental status, nausea, or ataxia.