IMPORTANT SAFETY INFORMATION Before you take NUEDEXTA, tell your doctor:

• If you are taking monoamine oxidase inhibitors (MAOIS), quinidine, or quinidine-related drugs. These can interact with NUEDEXTA causing serious side effects. MAOIS cannot be taken within 14 days before or after taking NUEDEXTA. • If you have previously had an allergic reaction to dextromethorphan, quinidine or quinidine-like drugs. • About all medicines, herbal supplements, and vitamins you take as NUEDEXTA and certain other medicines can interact causing side effects. • If you have had heart disease or have a family history of heart rhythm problems. NUEDEXTA may cause serious side effects, including changes in heart rhythm. If you have certain heart problems, NUEDEXTA may not be right for you. Your doctor may test your heart rhythm (heartbeats) before you start NUEDEXTA. • If you have myasthenia gravis.