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
Images: Related links to external sites (from Bing)
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 |