Ethosuximide Dosage

Medically reviewed by Drugs.com. Last updated on Jul 15, 2024.

Usual Adult Dose for Seizures

Initial dose: 500 mg orally once a day

• Increase dose in small increments, for example 250 mg daily every 4 to 7 days, until optimal seizure control with minimal side effects is achieved

Maintenance dose: Individualized; generally, a dose that provides efficacy and tolerability with a plasma level within the accepted therapeutic range (40 to 100 mcg/mL)

Comments:

• Doses exceeding 1.5 g per day should be administered only under strict supervision of a physician.
• For higher daily doses, consider twice a day dosing.
• This drug may be administered in combination with other anticonvulsants when other forms of epilepsy coexist.

Use: For the control of absence (petit mal) seizures.

Usual Pediatric Dose for Seizures

3 to 6 years old:
Initial dose: 250 mg orally once a day

6 years or older:
Initial dose: 500 mg orally once a day

Titration: Increase dose in small increments, for example 250 mg daily every 4 to 7 days, until optimal seizure control with minimal side effects is achieved
Maintenance dose: Individualized; generally, a dose that provides efficacy and tolerability with a plasma level within the accepted therapeutic range (40 to 100 mcg/mL)
Optimal dose for most pediatric patients: 20 mg/kg/day; some authorities have found doses up to 40 mg/kg/24 hours are needed to obtain therapeutic levels

Comments:

• Doses exceeding 1.5 g per day should be administered only under strict supervision of a physician.
• For higher daily doses, consider twice a day dosing.
• This drug may be administered in combination with other anticonvulsants when other forms of epilepsy coexist.

Use: For the control of absence (petit mal) seizures.

Renal Dose Adjustments

Renal disease: Administer with extreme caution

Liver Dose Adjustments

Liver disease: Administer with extreme caution

Dose Adjustments

Therapeutic blood level monitoring:

• Accepted therapeutic range: 40 to 100 mcg/mL

Concomitant Use with other Antiepileptic Drugs

• Periodic serum level determinations of antiepileptic drugs may be necessary
• This drug may elevate phenytoin serum levels
• Valproic acid may both increase and decrease ethosuximide levels

Changes to Dosing Regimen:

• Dose changes, as well as, the addition and/or elimination of other antiepileptic medications should be done slowly; avoid abrupt withdrawal

Precautions

NARROW THERAPEUTIC INDEX:

• This drug should be considered a narrow therapeutic index (NTI) drug as small differences in dose or blood concentrations may lead to serious therapeutic failures or adverse drug reactions.

Recommendations:

• Generic substitution should be done cautiously, if at all, as current bioequivalence standards are generally insufficient for NTI drugs.
• Additional and/or more frequent monitoring should be done to ensure receipt of an effective dose while avoiding unnecessary toxicities.

CONTRAINDICATIONS:

• Hypersensitivity to succinimides

Safety and efficacy have not been established in patients younger than 3 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• Take orally
• An adequately calibrated measuring device such as an oral syringe, should be used to measure liquid doses

Storage requirements:

• Oral solution: Protect from freezing and light

General:

• Using this drug as monotherapy in patients with mixed type of epilepsy may increase the frequency of grand mal seizures in some patients.
• Abrupt withdrawal may precipitate seizures; as with other antiepileptic drugs, dose increases and decreases should proceed slowly.

Monitoring:

• Blood counts, periodically, and if signs and/or symptoms of infection develop
• Urinalysis periodically
• Liver function tests periodically
• Monitor for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior
• Monitor for rash

Patient advice:

• Read the US FDA-approved patient labeling (Patient Information).
• Patients should understand the importance of strictly adhering to their dosing regimen.
• Patients should be appropriately counseled regarding the performance of potentially hazardous tasks.
• Patients should be instructed to contact their healthcare provider promptly if they develop a rash or signs and symptoms of an infection.
• Patients and/or caregivers should monitor for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior; behaviors of concern should be reported promptly.
• Women of childbearing potential should speak with their physician if they are or intend to become pregnant, or are breastfeeding.

See also:

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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