Ethosuximide

Zarontin is indicated for the control of absence (petit mal) epilepsy.

• Zarontin is administered by the oral route
• The initial dose for patients 3 to 6 years of age is one capsule (250 mg) per day; for patients 6 years of age and older, 2 capsules (500 mg) per day
• The dose thereafter must be individualized according to the patient's response
• Dosage should be increased by small increments
• One useful method is to increase the daily dose by 250 mg every four to seven days until control is achieved with minimal side effects
• Dosages exceeding 1.5 g daily, in divided doses, should be administered only under the strictest supervision of the physician
• The optimal dose for most
• Pediatric patients is 20 mg/kg/day
• This dose has given average plasma levels within the accepted therapeutic range of 40 to 100 mcg/mL
• Subsequent dose schedules can be based on effectiveness and plasma level determinations
• Zarontin may be administered in combination with other anticonvulsants when other forms of epilepsy coexist with absence (petit mal)
• The optimal dose for most
• Pediatric patients is 20 mg/kg/day

• Safety and effectiveness
• In pediatric patients below the age of 3 years have not been established. (See DOSAGE AND ADMINISTRATION section.)

• Inform patients of the availability of a Medication Guide, and instruct them to read the Medication Guide prior to taking Zarontin
• Instruct patients to take Zarontin only as prescribed
• Ethosuximide may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a motor vehicle or other such activity requiring alertness; therefore, the patient should be cautioned accordingly
• Patients taking ethosuximide should be advised of the importance of adhering strictly to the prescribed dosage regimen. …

CONTRAINDICATION Ethosuximide should not be used in patients with a history of hypersensitivity to succinimides.

Since Zarontin (ethosuximide) may interact with concurrently administered antiepileptic drugs, periodic serum level determinations of these drugs may be necessary (e.g., ethosuximide may elevate phenytoin serum levels and valproic acid has been reported to both increase and decrease ethosuximide levels).

Blood Dyscrasias: Blood dyscrasias, including some with fatal outcome, have been reported to be associated with the use of ethosuximide; therefore, periodic blood counts should be performed. Should signs and/or symptoms of infection (e.g., sore throat, fever) develop, blood counts should be considered at that point. Drug-Induced Immune Thrombocytopenia: Drug-induced immune thrombocytopenia (DITP) has been reported with ethosuximide. In the reported cases, the onset of symptoms occurred 1 to 3 weeks after initiation of ethosuximide; one patient had recurrence of symptoms within 1 day of a subsequent re-challenge with the drug. …

Body As A Whole: Allergic reaction, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). Gastrointestinal System: Gastrointestinal symptoms occur frequently and include anorexia, vague gastric upset, nausea and vomiting, cramps, epigastric and abdominal pain, weight loss, and diarrhea. There have been reports of gum hypertrophy and swelling of the tongue. Hemopoietic System: Hemopoietic complications associated with the administration of ethosuximide have included leukopenia, agranulocytosis, pancytopenia, with or without bone marrow suppression, eosinophilia, and thrombocytopenia (see WARNINGS ). …

Pregnancy: To provide information regarding the effects of in utero exposure to Zarontin, physicians are advised to recommend that pregnant patients taking Zarontin enroll in the NAAED Pregnancy Registry. This can be done by calling the toll free number 1-888-233-2334, and must be done by patients themselves. Information on the registry can also be found at the website: http://www.aedpregnancyregistry.org/ See WARNINGS .

Acute overdoses may produce nausea, vomiting, and CNS depression including coma with respiratory depression. A relationship between ethosuximide toxicity and its plasma levels has not been established. The therapeutic range of serum levels is 40 mcg/mL to 100 mcg/mL, although levels as high as 150 mcg/mL have been reported without signs of toxicity. Treatment: Treatment should include emesis (unless the patient is or could rapidly become obtunded, comatose, or convulsing) or gastric lavage, activated charcoal, cathartics, and general supportive measures. …

Store at 25° C (77° F); excursions permitted to 15–30° C (59–86° F) [see USP Controlled Room Temperature].

Take it when you remember, unless it is nearly time for the next dose. Then skip the missed one. Never take two doses at once to make up for it. Check your leaflet, as some medicines are different.