Classifications: central nervous system agent; succinimide anticonvulsant
Pregnancy Category: C
250 mg capsules; 250 mg/5 mL syrup
Succinimide anticonvulsant. Usually ineffective in management of psychomotor or major motor seizures.
Reduces frequency of epileptiform attacks, apparently by depressing motor cortex and elevating CNS threshold to stimuli.
Management of absence (petit mal) seizures, myoclonic seizures, and akinetic epilepsy. May be administered with other anticonvulsants
when other forms of epilepsy coexist with petit mal.
Hypersensitivity to succinimides; severe liver or kidney disease; use alone in mixed types of epilepsy (may increase frequency
of grand mal seizures). Safety during pregnancy (category C), lactation, or in children <3 y is not established.
Adult/Child: PO 612 y, 250 mg b.i.d., may increase q47d prn (max: 1.5 g/d)
Child: PO 36 y, 250 mg/d, may increase q47d prn (max: 1.5 g/d)
CNS: Drowsiness, hiccups, ataxia, dizziness, headache, euphoria, restlessness, irritability, anxiety, hyperactivity, aggressiveness,
inability to concentrate, lethargy, confusion, sleep disturbances, night terrors, hypochondriacal behavior, muscle weakness,
fatigue. Special Senses: Myopia. GI: Nausea, vomiting, anorexia, epigastric distress, abdominal pain, weight loss, diarrhea, constipation, gingival hyperplasia. Urogenital: Vaginal bleeding. Hematologic: Eosinophilia, leukopenia, thrombocytopenia, agranulocytosis, pancytopenia, aplastic anemia, positive direct Coombs' test. Skin: Hirsutism, pruritic erythematous skin eruptions, urticaria, alopecia, erythema multiforme, exfoliative dermatitis.
Drug: Carbamazepine decreases ethosuximide levels; isoniazid significantly increases ethosuximide levels; levels of both phenobarbital and ethosuximide may be altered with increased seizure frequency. Herbal: Ginkgo may decrease anticonvulsant effectiveness.
Absorption: Readily absorbed from GI tract. Peak: 4 h; steady state: 47 d. Metabolism: Metabolized in liver. Elimination: Excreted slowly in urine; small amounts excreted in bile and feces. Half-Life: 30 h in children, 60 h in adults.
- Give with food if GI distress occurs.
- Store all forms at 15°30° C (59°86° F); capsules in tight containers, and syrup in light-resistant
containers; avoid freezing.
Assessment & Drug Effects
- Lab tests: Perform baseline and periodic hematologic studies, liver and kidney function.
- Monitor adverse drug effects. GI symptoms, drowsiness, ataxia, dizziness, and other neurologic adverse effects occur frequently
and indicate the need for dosage adjustment.
- Observe closely during period of dosage adjustment and whenever other medications are added or eliminated from the drug regimen.
Therapeutic serum levels: 4080 mcg/mL.
- Observe patients with prior history of psychiatric disturbances for behavioral changes. Close supervision is indicated. Drug
should be withdrawn slowly if these symptoms appear.
Patient & Family Education
- Discontinue drug only under physician supervision; abrupt withdrawal of ethosuximide (whether used alone or in combination
therapy) may precipitate seizures or petit mal status.
- Do not drive or engage in other potentially hazardous activities until response to drug is known.
- Monitor weight on a weekly basis. Report anorexia and weight loss to physician; may indicate need to reduce dosage.
- Do not breast feed while taking this drug without consulting physician.