Which of the following is a characteristic of an open formulary?

An open formulary is characterized by a wide range of medication options available to patients, which are often categorized into different tiers based on factors such as cost and coverage. In this context, stating that most of the drugs are covered under the appropriate tier accurately reflects the essence of an open formulary, as it indicates that a broad selection of medications can be accessed. This characteristic allows for flexibility and choice, enabling patients and healthcare providers to select the most suitable medications to meet specific health needs.

The other options do not align with the nature of an open formulary. Limited drug options would suggest a closed formulary approach, where fewer medications are available, while stating that no drugs are covered contradicts the foundational premise of any formulary system where medications should be available for patient access. Lastly, indicating that only generic drugs are allowed would not capture the essence of an open formulary, which includes both brand-name and generic options. Thus, the correct answer highlights the inclusive nature of an open formulary, emphasizing the coverage of most drugs.