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.