RxNorm API Changes
The following table lists the changes to the RxNorm API.

Release Date: October 27, 2016
Modules affected: getAllHistoricalNDCs, /rxcui/{rxcui}/allhistoricalndcs
Description of changes:
New function to provide past and present National Drug Codes (NDCs) for a concept
Release Date: January 21, 2016
Modules affected: getNDCProperties, /ndcproperties
Description of changes:
New function to provide NDC properties for an NDC, SPL Set Identifier or RxNorm concept.
Release Date: August 3, 2015
Modules affected: getAllNDCS, /allndcs
Description of changes:
New function to provide NDC history for a concept.
Release Date: June 29, 2015
Modules affected: getNDCStatus, /ndcstatus
Description of changes:
New function to provide NDC status.
Release Date: October 1, 2014
Modules affected: getQuantity, /rxcui/{rxcui}/quantity, getStrength, /rxcui/{rxcui}/strength, getSplSetId, /rxcui/{rxcui}/splsetid, approxMatch, /approx, findRemapped, /remap/{rxcui}
Description of changes:
Deprecated.
Release Date: September 4, 2014
Modules affected: getUNII, /rxcui/{rxcui}/unii
Description of changes:
Deprecated.
Release Date: March 3, 2014
Modules affected: getAllClasses, getClassMembers, getClassHierarchy(REST)
Description of changes:
New functions getAllClasses and getClassMembers. Change in the REST calling parameters in getClassHierarchy.
Release Date: December 17, 2013
Modules affected: filterByProperty, getRxProperty, getClassHierarchy, getAllProperties, getPropNames
Description of changes:
New functions filterByProperty, getRxProperty and getClassHierarchy have been added. The SCHEDULE property is now added to the list of returned properties. It represents the drug schedule (DCSA attribute in RXNSAT) and will be returned if it is defined by any of the non-proprietary sources.
Release Date: August 5, 2013
Modules affected: findRxcuiById, getIdTypes
Description of changes:
New ID type ATC (Anatomical Therapeutic Chemical) has been added to the list of searchable IDs for findRxcuiById.
Release Date: May 30, 2013
Modules affected: getApproximateMatch, approxMatch
Description of changes:
Function getApproximateMatch has been added to the API. This function should be used in place of approxMatch, which will be deprecated in the future. Several changes to the existing approximate match algorithm were made:
  • Spelling suggestions are now considered partial token matches, and therefore the score will be reduced. For example, if the input string was "Viagro" and the approximate match algorithm spelling corrected it to "Viagra", the top scores returned would have been 100 for all Viagra strings in the database. With the new change, the scores will be 75. The partial match score for a spelling suggestion depends on how close the suggestion is to the original word. With the spelling suggestion partial matches, very weak suggestions may no longer show up as results. Note that the comment field returned by getApproximateMatch will identify the spelling suggestions.
  • More than one spelling suggestion is now possible, if the suggestions are of equal closeness to the original word.
  • The number of entries returned has changed from twenty plus ties to a maximum value of twenty. For example, if there are 19 entries with a top score of 80, and 10 entries with a (second highest) score of 75, all 29 would be returned in the previous version. Now 19 entries will be returned. If more than twenty entries have a top score, all will be returned. Note that the maximum number of entries can be specified in the getApproximateMatch function.
Release Date: February 21, 2012
Modules affected: getRxcuiStatus
Description of changes:
Function getRxcuiStatus has been added to the API.
Release Date: December 14, 2011
Modules affected: getAllConceptsByTTY, getAllProperties, getPropNames, getPropCategories, findRxcuiById, getIdTypes
Description of changes:
Functions getAllConceptsByTTY, getAllProperties, getPropNames and getPropCategories have been added to the API. New ID types NDA (New Drug Application) and ANDA (Abbreviated New Drug Application) were added to the list of searchable IDs for findRxcuiById.
Release Date: October 13, 2011
Modules affected: getRelatedByType, getAllRelatedInfo
Description of changes:
The API has been changed to return data for the new TTYs introduced in the October release - SBDG, SCDG, and DFG.
Release Date: August 29, 2011
Modules affected: approxMatch, getProprietaryInformation
Description of changes:
Initial release of approxMatch, a function to find concepts which approximately match a given string. The getProprietaryInformation function has been modified to be able to search on an RxAUI.
Release Date: May 2, 2011
Modules affected: getRelatedByType, getAllRelatedInfo
Description of changes:
For getRelatedByType and getAllRelatedInfo, the determination of the related concepts has changed when starting or ending with an ingredient (PIN) concept. See the default path table for more details. This plus a query change was made to speed up the response time.
Release Date: January 31, 2011
Modules affected: getProprietaryInformation, getSourceTypes, getRelatedByType, getAllRelatedInfo
Description of changes:
The proxyTicket parameter should be generated from the UMLS Terminology Services (UTS) authorization server for use in getProprietaryInformation.
A new function called getSourceTypes was added to return the valid source abbreviations which can be used in getProprietaryInformation.

For getRelatedByType and getAllRelatedInfo, the determination of the related concepts has changed when starting or ending with a precise ingredient (PIN) concept. See the default path table for more details.

Release Date: December 1, 2010
Modules affected: findRemapped
Description of change:
A new function findRemapped was added.
Release Date: September 7, 2010
Modules affected: getRelatedByType, getAllRelatedInfo, getRelatedByRelationship, getTermTypes, getRelaTypes
Description of change:
The September 2010 release of RxNorm data introduced the MIN (multiple ingredient) term type, and includes new relationships - "part_of" and "has_part" between MIN and PIN/IN term types, and "ingredients_of" and "has_ingredients" between MIN and SCD term types.
Release Date: August 10, 2010
Modules affected: getSplSetId
Description of change:
New function to get the Structured Product Label set identifiers for a given concept.
Release Date: August 6, 2010
Modules affected: findRxcuiById
Description of change:
Allowing search on HIC_SEQN.
Release Date: July 22, 2010
Modules affected: findRxcuiByString
Description of change:
Addition of a fourth parameter - searchType. This allows users to specify whether an exact match or normalized string search is to be executed. Previously, exact match searching was done.
Release Date: June 30, 2010
Modules affected:
Description of change:
Introduction of the RxNorm RESTful Web API. For details see the RxNorm RESTful Web API User's Guide.
Release Date: June 10, 2010
Modules affected: findRxcuiById
Description of change:
Allowing search on NUI and SPL_SET_ID.
Release Date: April 14, 2010
Modules affected: getUNII
Description of change:
New function added to user documentation and to the WSDL file.
Release Date: February 15, 2010
Modules affected: getStrength, getQuantity
Description of change:
New functions added to user documentation and to the WSDL file.
Release Date: October 7, 2009
Modules affected: getDisplayTerms
Description of change:
New function added to user documentation and to the WSDL file.
Release Date: August 17, 2009
Modules affected: findRxcuiById, getIdTypes
Description of change:
The GCN identifier has been replaced by GCN_SEQNO.
Release Date: July 8, 2009
Modules affected: getAllRelatedInfo, getRxConceptProperties, getRelatedByType, getTermTypes
Description of change:
The PIN (precise ingredient) term type was added starting with the July 2009 release of the RxNorm data set. RxNorm terms of this type previously had an IN term type. The PIN term type will be returned as part of the structure returned by getAllRelatedInfo. PIN is also now a valid input type for getRelatedByType.
Release Date: April 28, 2009
Modules affected: findRxcuiById, with idType = "NDC"
Description of change:
The change fixes a problem in the findRxcuiById function when used with the NDC identifier type. In certain cases RxCUIs were not returned when the NDC identifier was contained in more than one concept. This problem occurred regardless of the value of the allSourcesFlag parameter.
Release Date: March 23, 2009
Modules affected: getRelatedByType, getAllRelatedInfo
Description of change:
The change fixes a problem in the getRelatedByType and the getAllRelatedInfo functions when the term type (TTY) associated with the RxCUI was a branded pack (BPCK). In certain cases the related ingredient (IN) and clinical drug component (SCDC) concepts were not returned.