A list of medications available for use within a health care system is called a:

The primary function of a prescription formulary is to specify particular medications that are approved to be prescribed under a particular insurance policy. Formularies are developed by evaluating the safety, efficacy, and cost-effectiveness of various drugs. With a closed formulary the insurance policy won't pay for drugs that are not on the list. An open formulary allows drugs that are not on the list, but will generally charge a higher co-pay for those drugs.