The effects of Vimpat were first tested in experimental models before being studied in humans.
The effectiveness of Vimpat taken by mouth has been compared with that of placebo (a dummy treatment) in three main studies involving a total of 1,308 patients. Patients added Vimpat at a dose of 200 mg, 400 mg or 600 mg a day, or placebo to their existing treatment of up to three other anti-epileptic medicines. The main measure of effectiveness was the number of patients whose number of seizures was at least halved after 12 weeks of treatment with a stable dose.
Two additional studies looked at the appropriate duration of the infusion for Vimpat solution and compared its safety with that of placebo infusions in a total of 199 patients.