Ethosuximide

14 interactions 127 cited references
Also sold as: Zarontin Zarontin®
About Ethosuximide

Ethosuximide is used to control absence seizures (petit mal) (a type of seizure in which there is a very short loss of awareness during which the person may stare straight ahead or blink his eyes and does not respond to others). Ethosuximide is in a class of medications called anticonvulsants. It works by reducing abno… Read the full Ethosuximide drug information page →

Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated Aug 9, 2026 · Editorial policy · Data sources

Sources: FDA prescribing information (Structured Product Labeling), the published literature cited in each entry, DDInter 2.0 (a major open-access drug-interaction database), and legacy DrugBank interaction data distributed by the NIH's RxNav service (decommissioned in 2024) — analyzed and reviewed by our pharmacist team. How we build this library →

Most serious with: Calcifediol Fosphenytoin Hydroxychloroquine Nevirapine Orlistat Phenytoin
8 Major 6 Moderate
All (14) Major (8) Moderate (6)

Major

Ethosuximide Calcifediol Rayaldee Altered serum levels of calcifediol Details Ethosuximide Fosphenytoin Cerebyx Reduced ethosuximide exposure and an increased phenytoin or fosphenytoin (prodrug of phenytoin) exposure and risk of toxicity Details Ethosuximide Hydroxychloroquine Plaquenil Impaired antiepileptic activity Details Ethosuximide Nevirapine Viramune Reduced ethosuximide exposure and reduced nevirapine exposure Details Ethosuximide Orlistat Alli Reduced efficacy of anticonvulsant Details Ethosuximide Phenytoin Dilantin Reduced ethosuximide exposure and an increased phenytoin or fosphenytoin (prodrug of phenytoin) exposure and risk of toxicity Details Ethosuximide Pimozide An increased risk of seizure Details Ethosuximide Valproic Acid Depakene® An increased risk of ethosuximide toxicity Details

Moderate

Ethosuximide Carbamazepine Carbatrol Reduced succinimide (ethosuximide, phensuximide) exposure and potential loss of efficacy Details Ethosuximide Evening Primrose Reduced anticonvulsant effectiveness Details Ethosuximide Folic Acid Folacin Reduced folic acid exposure and reduced efficacy of folic acid Details Ethosuximide Ginkgo Decreased anticonvulsant effectiveness Details Ethosuximide Phenobarbital Fidoquel Decreased ethosuximide serum concentrations Details Ethosuximide Ritonavir Norvir Increased ethosuximide serum concentrations and potential toxicity (nausea, drowsiness, dizziness, weakness, headache) Details

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