When a patient goes to a pharmacy to pick up a prescription, a pharmacist may provide the patient with an equivalent and interchangeable generic medicine without having to consult the prescriber. This practice is called substitution. Each state has its own laws or regulation regarding the use of brand-name and generic prescription drugs, such as when a generic medication may be substituted for a brand-name medication. These laws, regulations and rules that govern the practice of pharmacy in each state are called pharmacy practice acts.
Because biosimilars were not available when generic substitution laws were developed, states must continue to update their pharmacy practice acts to allow for substitution of interchangeable biologic products.