Trimethadione (brand name is TRIDIONE) is an oxazolidinedione compound that was developed as an antiepileptic agent for control of petit mal seizures that are refractory to treatment with other drugs. Tridione does not modify the maximal seizure pattern in patients undergoing electroconvulsive therapy and has a sedative effect that may increase to the point of ataxia when excessive doses are used. Trimethadione acts as a voltage-activated T-type Ca2+ channel blocker. Trimethadione is rapidly absorbed from the gastrointestinal tract. It is demethylated by liver microsomes to the active metabolite, dimethadione. Approximately 3% of a daily dose of tridione is recovered in the urine as the unchanged drug. The majority of trimethadione is excreted slowly by the kidney in the form of dimethadione.

Mephobarbital us a barbiturate derivative used primary as an anticonvulsant, but also as a sedative and anxiolytic. Marketing of mephobarbital was discontinued in 2012.

2,5-Dimethyl-N-Phenyl-3H-diazaphophol-4-imine is a quinonoid tautomer of GABAA and GABAB agonist progabide. According to quantum mechanical calculations, a quinonoid form is predominant in polar solvents, while aromatic tautomer is prevalent in apolar solvents. Progabide is a prodrug of gamma-aminobutyric acid and was investigated for the treatment of epilepsy, Parkinson's disease, schizophrenia, clinical depression, anxiety disorder, and other diseases. Progabide was marketed in France by Sanofi Aventis under tradename Gabrene for use in monotherapy and also as adjunctive therapy for generalized tonic-clonic, myoclonic, partial seizures, and for Lennox‐Gastaut syndrome, in both children and adults.

Valpromide (2-propylpentanamide) is a derivative of valproic acid. Bio-pharmacological data show several possible mechanisms of action involving an increase in GABA levels in brain as well as changes in membrane conductance on neurons. Valpromide has been shown to decrease aggressivity in stress-induced animals, to regulate anxious induced behaviours, as well as to potentiate central sedative compounds. It produces a significant increase of cognitive functions. Psychopathological experiments have shown: a wakening of personality, euphoric effects, an improvement of social behaviour, a stabilization of mood in affective disorders. Valpromide is indicated for the treatment of bipolar disorder (manic episodes). It is marketed in some Europe countries.

Carisbamate is an experimental anticonvulsant drug that was under development by Johnson & Johnson Pharmaceutical Research and Development but never marketed. Acute and chronic nonclinical toxicological studies have not revealed any significant abnormalities other than dose-related CNS toxicity. Carisbamate displays high potency in a broad range of rodent seizure and epilepsy models at doses well below those that produce CNS toxicity. The exact mechanism of action is unknown but neuroprotective and antiseizure activity of Carisbamate likely results in part from decreased calcium accumulation through blockade of T-type Ca2+ channels. A phase II clinical trial in the treatment of partial seizures demonstrated that the compound has efficacy in the treatment of partial seizures and a good safety profile. In large multicenter phase III clinical trial for the treatment of partial seizures carisbamate at doses of 300, 800, and 1,600 mg/d was effective as adjunctive therapy for reducing the frequency of partial-onset seizures. The most common adverse events, encountered mainly at daily doses of 1000 mg or more, were CNS-related, including headache, dizziness, somnolence, and nausea. In another phase III clinical trial, carisbamate was not more efficacious in migraine prophylaxis than placebo, but carisbamate monotherapy was well tolerated at doses up to 600 mg per day. Johnson & Johnson received provisional approval by the FDA to market carisbamate under the brand name of Comfyde. However, on August 21, 2009, Johnson & Johnson reported that the FDA had failed to give marketing approval.

Pheneturide ((brand names Benuride, Deturid, Pheneturid, Septotence, Trinuride), a decarboxylation product of phenobarbital, has been shown to be an effective drug against seizures, and in particular psychomotor seizures. It has being marketed in Europe, including in Poland, Spain, and the United Kingdom. Pheneturide is supplied in compressed tablets each containing 200 mg. of the drug. It can also be obtained in compound tablets (" trinuride ') each of which contain 200 mg. of pheneturide, 40 mg. of diphenylhydantoin, and 15 mg. of phenobarbitone. Animal experiments have shown that pheneturide protects against drug-induced and electrically induced convulsions.

Ethadione is an oxazolidine derivative. It has been used in the treatment of seizures.

Sulthiame is a potent inhibitor of carbonic anhydrase II, VII, IX, and XII. Sulthiame is an antiepileptic drug that is used widely in some European countries and in Israel. Sometimes it is used as an additional (add-on) antiepileptic medicine in non responders, alongside an existing antiepileptic medicine.

Oxcarbazepine and its active metabolite (10,11-dihydro-10-hydroxy-carbazepine, MHD) have been effective in animal models of epilepsy that generally predict efficacy in generalized tonic-clonic seizures and partial seizures in humans. The pharmacokinetic profile of oxcarbazepine is less complicated than that of carbamazepine, with less metabolism by the cytochrome P450 system, no production of an epoxide metabolite, and lower plasma protein binding. The clinical efficacy and tolerability of oxcarbazepine have been demonstrated in trials in adults, children, and the elderly. The pharmacological activity of oxcarbazepine is primarily exerted through the 10-monohydroxy metabolite (MHD) of oxcarbazepine. The precise mechanism by which oxcarbazepine and MHD exert their antiseizure effect is unknown; however, in vitro electrophysiological studies indicate that they produce blockade of voltage-sensitive sodium channels, resulting in stabilization of hyperexcited neural membranes, inhibition of repetitive neuronal firing, and diminution of propagation of synaptic impulses. These actions are thought to be important in the prevention of seizure spread in the intact brain. In addition, increased potassium conductance and modulation of high-voltage activated calcium channels may contribute to the anticonvulsant effects of the drug.