The service provides listings for a subset of drugs available to be prescribed in the United States from the larger list of all prescription medications maintained by the provider's [[http://www.programmableweb.com/api/rxnorm RxNorm service]]. Prescribable listings also include selected popular over-the-counter (OTC) medications that doctors frequently prescribe. The listing omits drugs available only in countries other than the U.S. and those usable only for veterinary purposes.
API methods support retrieval of an updated list of drugs with correct names, ingredients, and system identifiers. Methods also support access to descriptive information, such as NDC and UNII codes, relationships to other drugs on the list, and rankings by prescription frequency.