Ethosuximide 250mg, 250mg/5ml Suppliers & Bulk Manufacturers

Available Forms: Capsules / Oral Solution

Available Strengths: 250mg, 250mg/5ml

Reference Brands: Zarontin (USA)

Category: Neurology

Ethosuximide is an anticonvulsant medication belonging to the succinimide class. It is primarily used to treat absence seizures, particularly in children. Ethosuximide works by inhibiting T-type calcium channels in the thalamus, which are believed to play a key role in generating the abnormal electrical activity associated with absence seizures.

Product Description:

Ethosuximide is a succinimide anticonvulsant that blocks low-threshold T-type calcium channels in thalamic relay neurons. Those channels drive the rhythmic three-per-second thalamocortical oscillation behind the spike-and-wave discharge of absence seizures, which is why ethosuximide is highly effective against absences and ineffective against almost every other seizure type. In a large randomised trial of childhood absence epilepsy it matched valproate for seizure control with fewer attentional adverse effects, and it is first-line for that syndrome.

Because it does not protect against generalised tonic-clonic seizures, children with mixed seizure types need a broader-spectrum drug alongside it or instead of it. Gastrointestinal upset, hiccups, drowsiness and headache are the usual adverse effects. Blood dyscrasias, systemic lupus erythematosus and severe skin reactions are rare but recognised, so blood counts are checked if fever or sore throat develops.

Sourcing notes. An old, inexpensive drug with a very narrow supplier base, and it has been in recurrent shortage in several markets — continuity of supply is a larger concern than price. The oral solution carries much of the paediatric volume and is a separate registration from the capsules. Capsules contain the drug as a liquid-filled soft gelatin form, so the manufacturer needs soft-gel capability; that alone rules out many generic manufacturers.