Ethosuximide

INDICATIONS AND USAGE Ethosuximide is indicated for the control of absence (petit mal) epilepsy.

DOSAGE AND ADMINISTRATION Ethosuximide Oral Solution USP is administered by the oral route. The initial dose for patients 3 to 6 years of age is one teaspoonful (250 mg) per day; for patients 6 years of age and older, 2 teaspoonfuls (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. Ethosuximide 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.

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

ADVERSE REACTIONS 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 ). Nervous System: Neurologic and sensory reactions reported during therapy with ethosuximide have included drowsiness, headache, dizziness, euphoria, hiccups, irritability, hyperactivity, lethargy, fatigue, and ataxia. Psychiatric or psychological aberrations associated with ethosuximide administration have included disturbances of sleep, night terrors, inability to concentrate, and aggressiveness. These effects may be noted particularly in patients who have previously exhibited psychological abnormalities. There have been rare reports of paranoid psychosis, increased libido, and increased state of depression with overt suicidal intentions. Integumentary System: Dermatologic manifestations which have occurred with the administration of ethosuximide have included urticaria, pruritic erythematous rashes, Stevens-Johnson syndrome, and hirsutism. Special Senses: Myopia. Genitourinary System: Vaginal bleeding, microscopic hematuria. To report SUSPECTED ADVERSE REACTIONS, contact PAI Pharma at 1-800-845-8210 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Interactions: Since 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).

DESCRIPTION Ethosuximide is an anticonvulsant succinimide, chemically designated as alpha-ethyl-alpha-methyl-succinimide, with the following structural formula: Each teaspoonful (5 mL), for oral administration, contains 250 mg ethosuximide, USP. Also contains citric acid, FD&C Red No. 40, FD&C Yellow No. 6, cherry-raspberry flavoring, glycerin, purified water, saccharin sodium, sodium benzoate, sodium citrate, and sucrose. Sodium hydroxide may be used for pH adjustment. The pH range is 5.0 to 6.5. Chemical Structure

OVERDOSAGE 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. Hemodialysis may be useful to treat ethosuximide overdose. Forced diuresis and exchange transfusions are ineffective.

HOW SUPPLIED Ethosuximide oral solution, USP 250 mg/5 mL is supplied in bottles of 16 fl. oz. (473 mL) NDC 62135-064-047. Each 5 mL of oral solution contains 250 mg ethosuximide in a raspberry flavored base. Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Protect from freezing and light. Dispense in a tight, light-resistant container with a child-resistant closure. Manufactured for: Chartwell RX, LLC. ​​​​​​​Congers, NY 10920 L72894 Rev: 05/2026