Effect of concomitant treatment with viloxazine extended-release and stimulants in adults with Attention-Deficit/Hyperactivity Disorder: Case series from an open-label extension study

Objective: Review safety and efficacy outcomes for participants with concomitant stimulant use in an open-label extension (OLE) after completing a phase 3, placebo-controlled, double-blind (DB) trial of viloxazine extended-release (ER) in adult Attention-Deficit/Hyperactivity Disorder (ADHD).
Methods: Participants completing the DB trial [NCT04016779] had the option to receive viloxazine ER in an OLE [NCT04143217]. Viloxazine was flexibly titrated between 200-600 mg/day. Adjunctive stimulant use was permitted following Week 12 at investigator’s discretion. Safety and efficacy measures were assessed descriptively. The trial was planned for 3 years or until commercial availability.
Results: Few participants (n/N&#3f10/159, 6% of safety population) were prescribed adjunctive stimulants (amphetamines n=6, methylphenidate n=4). Participants were prescribed stimulant for approximately 1/3 of their total time in the study. All participants were receiving viloxazine ER ≥ 400 mg/day at stimulant initiation. No participant experienced new onset of a treatment-related adverse event (AE) during stimulant use, and none had AEs leading to discontinuation. Four participants (40%) had transient blood pressure elevation, but none were persistent nor recorded as AEs. Small sample size and the flexible nature medication dosing prevented rigorous efficacy assessment; however, when comparing visits immediately before and after stimulant prescription, 63% showed improvement (reduction in score) in ADHD and in executive function symptoms.
Conclusions: No safety issues were noted with combined stimulant and viloxazine ER use in this small case series of adults with ADHD. Further evaluation of concomitant use in a larger adult sample is warranted.