The Anatomical, Therapeutic, Chemical Classification System with Defined Daily Doses (ATC/DDD)

Identifying and definitional attributes

Metadata item type:Classification Scheme
Synonymous names:The ATC/DDD system
METeOR identifier:334667
Registration status:Health, Standard 07/12/2005
National Health Performance Authority (retired), Retired 01/07/2016

The ATC/DDD system classifies therapeutic drug utilisation.

The purpose of the ATC/DDD system is to serve as a tool for drug utilization research in order to improve quality of therapeutic drug use.

Classification structure:

In the ATC/DDD classification system, drugs are divided into different groups according to the organ or system on which they act and their chemical, pharmacological and therapeutic properties.

Drugs are classified into five different levels. Drug consumption statistics (international and other levels) can be presented for each of these five levels.

Collection and usage attributes


The Anatomical therapeutic classification (AT) was developed by the European Pharmaceutical Market Research Association (EPhMRA). The ATC/DDD system and the AT classification have the same origin, but are developed for different purposes. Comparative tables are available.

The ATC classification used the International Nonproprietary Name (INN) whenever possible.

Source and reference attributes

Reference documents:

The Guidelines for ATC classification and DDD assignment were published for the first time in the current format in 1990. The Guidelines are published in all 3 languages in paper format only.

The Index was published as a paper copy in the current format in 1990 for the first time. The Index is published in the following languages and formats: English (all available indexes), German (paper version only), Spanish (paper version only).

An online searchable database is also available at

Revision status:

The system has been used for statistics since 1975.

Years between revisions - 1

Year of last revision - 2004

Latest revision number - 6 for the Guidelines in the current format, 13 for the Index in the current format.

Relational attributes

Value Domains based on this classification scheme:

Medication type (ATC/DDD) code A[{NN}AA{NN}] Health, Standard 25/08/2011
National Health Performance Authority (retired), Retired 01/07/2016