Open-label Study to Evaluate Long-term Safety and Efficacy of SPN-812 (Viloxazine Extended-release Capsule)

This is a multicenter open-label extension study assessing long term safety and efficacy of SPN-812 (viloxazine extended-release capsules) in pediatric subjects with ADHD who completed a randomized, double-blind, placebo-controlled clinical trial, including (A) a Phase 2 (Study 812P202: children 6 to 12 years of age) or a Phase 3 trial (Study 812P301 or 812P303: children 6 to 11 years of age; or Study 812P302 or 812P304: adolescents 12 to 17 years of age) or (B) a Phase 4 trial (Study 812P401: preschool-age children, 4-5 years of age). The study is divided into two phases, Optimization and Maintenance phases. Subjects in Cohort 'A' who completed a Phase 2 or Phase 3 trial followed protocol Schedule 'A' (exposure up to 72 months). Subjects in Cohort 'B' who complete the Phase 4 trial will follow Schedule 'B' (exposure up to 6 months).