MAR-ETHOSUXIMIDE

1 Dosing Considerations As with other anticonvulsants, it is important to proceed slowly when increasing or decreasing dosage, as well as when adding or eliminating other medication. Abrupt withdrawal of anticonvulsant medication may precipitate absence (petit mal) status.

Patients taking ethosuximide should be advised of the importance of adhering strictly to the prescribed dosage regimen. 2 Recommended Dose and Dosage Adjustment Initial dose: children aged 3 to 6 years, 250 mg daily; older patients, 500 mg daily in divided doses.

The dose thereafter must be individualized according to response and tolerance. g. increase daily dose by 250 mg every 4 to 7 days until control is Serious Warnings and Precautions Blood dyscrasias, including with fatal outcomes, have been reported to be associated with the use of ethosuximide; therefore, periodic blood counts should be performed.

, sore throat, fever) develop, blood count determinations should be considered at that point (see 7 WARNINGS AND PRECAUTIONS, Hematologic). Product Monograph MAR-ETHOSUXIMIDE Page 5 of 18 achieved with minimal side effects. 5 g in divided doses frequently controls seizures; however, it may be necessary to exceed this amount by slow increases and careful evaluation of patient’s response.

5 g daily, in divided doses, should be administered only under the strictest supervision of the physician. The optimal dose for most children is 20 mg/kg/day. This dose has given average plasma levels within the accepted therapeutic range of 280 to 710 mcmol/L (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 dosage for most children is 20 mg/kg/day.

4 Administration Ethosuximide can be taken with or without food. 5 Missed Dose In case of missed dose, the next dose should be taken as scheduled. A double dose should not be taken.

5 Post-Market Adverse Reactions Gastrointestinal: 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.

Genitourinary: microscopic hematuria and vaginal bleeding.

Hemopoietic:

Leukopenia, agranulocytosis, pancytopenia, aplastic anemia, with or without bone marrow suppression, eosinophilia, and thrombocytopenia.

Integumentary:

Dermatologic manifestations which have occurred with the administration of ethosuximide have included urticarial, Stevens-Johnson syndrome (SJS), Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), systemic lupus erythematosus, and pruritic erythematous rashes.

Miscellaneous: myopia and hirsutism.

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.

, Hematologic). Product Monograph MAR-ETHOSUXIMIDE Page 5 of 18 achieved with minimal side effects. 5 g in divided doses frequently controls seizures; however, it may be necessary to exceed this amount by slow increases and careful evaluation of patient’s response.

5 g daily, in divided doses, should be administered only under the strictest supervision of the physician. The optimal dose for most children is 20 mg/kg/day. This dose has given average plasma levels within the accepted therapeutic range of 280 to 710 mcmol/L (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 dosage for most children is 20 mg/kg/day.

4 Administration Ethosuximide can be taken with or without food. 5 Missed Dose In case of missed dose, the next dose should be taken as scheduled. A double dose should not be taken. 5 OVERDOSAGE Symptoms: 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 is 280 to 710 mcmol/L, although levels as high as 1,050 mcmol/L 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. 6 DOSAGE FORMS, STRENGTHS, COMPOSITION AND PACKAGING Table 1 – Dosage Forms, Strengths, Composition and Packaging Route of Administration Dosage Form / Strength/Composition Non-medicinal Ingredients Oral Capsules 250 mg D&C Yellow No.

• MAR-ETHOSUXIMIDE is contraindicated in patients who are hypersensitive to ethosuximide or to any ingredient in the formulation, including any non-medicinal ingredient, or component of the container. For a complete listing, see 6 DOSAGE FORMS, STRENGTHS, COMPOSITION AND PACKAGING.

• MAR-ETHOSUXIMIDE should not be used in patients who are hypersensitive to succinimides or components of these products.