Subjects will receive repeat doses of ezogabine for up to 34 days starting at a dose of 100 mg IR TID (300mg TDD) with a standard meal (to be consumed 30 min prior to dosing) for Days 1-3, on days 4-6 subjects will receive 150mg IR TID (450mg TDD). On Day 7 through to the end of the study subjects will receive ezogabine (Mr or IR) at a dose of 600mgTDD.