Abstract: A method of operating a formulary and software therefore comprising a unique formulary maintenance tool are disclosed which allows for much greater participation of a PBM In the maintenance and upgrading of formularies. The method and software allow the PBM to create a wide range of useful and efficient proxies (“top down” operation) and not wait for organizations such as CMS or clients to define specific and limited drugs (“bottom up” operation). The system retains the ability to incorporate CMS- and client-defined proxies but also allows the PBM to create such proxies on its own from competent source information. It also includes sorting, navigation, comparison and communication capabilities which will result in significantly more efficient claim adjudication and system maintenance.