There is an increasing number of new AED formulations marketed and awaiting approval. Some of these are generic versions of marketed AEDs. Others are therapeutic substitutions, providing a new version of a branded drug. Patients and doctors need to understand the differences between immediate and long-acting formulations of a drug. They need to be advised of the particular issues in epilepsy when generics are substituted for branded medications. This section will address those issues, as well as the formulary/copay implications and various state “dispense as written” statutes.