Placebo
DrugFor the 12-day Titration Phase, one matching placebo tablet will be administered twice daily and increased by 1 matching placebo tablet every 3 days up to maximum of 4 matching placebo tablets twice daily (placebo tablet matched to rufinamide total daily dose of 3200 mg). For the 12 week maintenance phase, 4 placebo tablets matching to rufinamide maintenance doses of 1600 mg twice daily (3200 mg total daily dose) will be administered. Similar to the dose reduction permitted in the rufinamide group, participants in placebo group will be allowed only during the Titration Phase to have the dose reduced to 3 placebo tablets twice daily.