What defines a negative formulary state?

A negative formulary state is characterized by the establishment of a list of specific medications for which substitution with a generic equivalent is not permitted. This list is usually created and maintained by the state's pharmacy board or regulatory authority. The rationale behind this is to ensure patient safety and maintain the efficacy of certain medications that may not have an equivalent generic form due to differences in formulation or bioavailability.

In such a state, the prescription of the drugs listed in this formulary must be filled with the brand-name medication unless there is explicit authorization to use a different formulation. This process helps protect patients who may be on particularly sensitive medications where generic substitution could lead to adverse effects or reduced therapeutic outcomes.

The other provided options do not accurately reflect the specific characteristics of a negative formulary state. For example, allowing substitutions for any drug contradicts the core function of a negative formulary. Similarly, a complete prohibition on the use of generics describes a different regulatory approach altogether and does not reflect the concept of having a carefully curated list of exceptions.