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Mesantoin Dosage

Medically reviewed by Last updated on Mar 28, 2022.

Generic name: mephenytoin
Dosage form: Tablets, USP

Dosage of antiepileptic therapy should be adjusted to the needs of the individual patient. Maintenance dosage is that smallest amount of antiepileptic necessary to suppress seizures completely or reduce their frequency. Optimum dosage is attained by starting with ½ or 1 tablet of Mesantoin® (mephenytoin) per day during the first week and thereafter increasing the daily dose by ½ or 1 tablet at weekly intervals. No dose should be increased until it has been taken for at least 1 week.

The average dose of Mesantoin® (mephenytoin) for adults ranges from 2-6 tablets (0.2-0.6 Gm.) daily. In some instances it may be necessary to administer as much as 8 tablets or more daily in order to obtain full seizure control. Pediatric patients usually require from 1-4 tablets (0.1-0.4 Gm.) according to nature of seizures and age.

When the physician wishes to replace the anticonvulsant now being employed with Mesantoin® (mephenytoin), he/she should give ½-1 tablet of Mesantoin® (mephenytoin) daily during the first week and gradually increase the daily dose at weekly intervals while gradually reducing that of the drug being discontinued. The transition can be made smoothly over a period of 3-6 weeks. If seizures are not completely controlled with the dose so attained, the daily dose should then be increased by a one-tablet increment at weekly intervals to the point of maximum effect. If the patient had also been receiving phenobarbital, it is well to continue it until the transition is completed, at which time gradual withdrawal of the phenobarbital may be tried.

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