II. Indications
III. Mechanism
- Succinimide anticonvulsant
- Partial Antagonist of T-type Calcium channels within thalamic Neurons
- Decreases burst firing of thalamocortical Neurons, stabilizing CNS nerve activity
IV. Dosing: Absence Seizures
- Therapeutic level: 40 to 100 mcg/ml
- Adults (and children age >6 years old)
- Start 500 mg orally once daily
- May increase dose by 250 mg/day every 4 to 7 days
- Maximum: 1.5 grams/day
- Children (ages 3 to 6 years old)
- Start 250 mg orally once daily
- May increase dose by 250 mg/day every 4 to 7 days
- Target dose: 20 mg/kg/day
-
Renal Dosing (CrCl <10 ml/min)
- Reduce dose 25%
V. Safety
- Pregnancy Category C
- Considered Safe in Lactation
- Monitor Complete Blood Count (cbc), and periodic Urinalysis and Liver Function Tests
VI. Metabolism
- Hepatic metabolism
- Highly Protein bound
- Half Life increased in liver disease and in children
VII. Adverse Effects
- Dose dependent effects (decreases overtime with use, and with divided dosing)
- Serious
- Neutropenia (rare)
- Mild Leukopenia, however, is common
- Increased Generalized Tonic Clonic Seizures
- Neutropenia (rare)
VIII. Drug Interactions
-
Valproic Acid
- Valproic Acid increases Ethosuximide levels
- Ethosuximide decreases valproic levels
-
Phenytoin
- Ethosuximide increases Phenytoin levels
-
Primidone
- Ethosuximide decreases Primidone levels
IX. Resources
- Ethosuximide (DailyMed)
X. References
- (2022) Presc Lett, Resource #361206, Antiseizure Medications
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 56-7
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
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Related Studies
ethosuximide (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
ETHOSUXIMIDE 250 MG CAPSULE | Generic | $0.40 each |
ETHOSUXIMIDE 250 MG/5 ML SOLN | Generic | $0.09 per ml |
Ontology: Ethosuximide (C0015043)
Definition (NCI) | A succinimide with anticonvulsant activity. The exact mechanism of action is not entirely understood, but most likely ethosuximide exerts its effects by partial antagonism of T-type calcium channels of the thalamic neurons. This leads to a decrease in burst firing of thalamocortical neurons, which stabilizes the nerve activity in the brain and prevents seizures. |
Definition (MSH) | An anticonvulsant especially useful in the treatment of absence seizures unaccompanied by other types of seizures. |
Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
MSH | D005013 |
SnomedCT | 322899006, 387244008, 44790008 |
LNC | LP16137-9, MTHU004937 |
English | Ethosuximide, Ethosuccimid, Ethylmethylsuccimide, ethosuximide, 2,5-Pyrrolidinedione, 3-ethyl-3-methyl-, 3-Ethyl-3-methylpyrrolidine-2,5-dione, ethosuximide (medication), ETHOSUXIMIDE, Ethosuximide [Chemical/Ingredient], Ethosuximide (product), Ethosuximide (substance) |
Swedish | Etosuximid |
Czech | ethosuximid |
Finnish | Etosuksimidi |
Italian | Etosuccimide, Etil-metil-succimide, Etosuximide |
Russian | ETOSUKTSIMID, ETOSUKSIMID, ЭТОСУКСИМИД, ЭТОСУКЦИМИД |
Polish | Etosukcynimid, Ronton, Zarontyna |
Japanese | エトスクシミド, エトサクシミド |
Spanish | etosuximida (producto), etosuximida (sustancia), etosuximida, Etosuximida, Etosuccimida |
French | Éthosuximide |
German | Ethosuccimid, Ethosuximid |
Portuguese | Etossuccimida, Etossuximida |