Antibiotic stewardship programs are designed to optimize antimicrobial use, improve patient outcomes, reduce antimicrobial resistance, and decrease unnecessary costs. The CBIC Certified Infection Control Exam Study Guide (6th edition) identifies formulary restriction and preauthorization as key core strategies within effective antimicrobial stewardship programs. A closed formulary specifically refers to a system in which access to certain antibiotics is restricted and requires prior approval before dispensing.

In a closed formulary model, prescribers must obtain authorization—often from infectious diseases specialists, pharmacy, or an antimicrobial stewardship team—before selected antimicrobial agents can be used. This approach ensures that high-risk, broad-spectrum, or high-cost antibiotics are used only when clinically appropriate. By requiring approval, the organization promotes judicious antibiotic selection, prevents unnecessary exposure, and supports resistance prevention efforts.

Option B describes de-escalation, which is another stewardship strategy but does not define a closed formulary. Option C refers to antibiotic cycling, a controversial and less-supported strategy. Option D is incorrect because a closed formulary does not merely limit availability; rather, it controls access through approval mechanisms.

For the CIC® exam, it is critical to distinguish between stewardship strategies. A closed formulary is best characterized by mandatory approval prior to dispensing, making option A the most accurate answer according to the Study Guide’s antimicrobial stewardship framework.

==========