[1] It is controlled by the World Health Organization Collaborating Centre for Drug Statistics Methodology (WHOCC), and was first published in 1976.
There are 14 main groups:[10] Example: C Cardiovascular system The second level of the code indicates the therapeutic subgroup and consists of two digits.
The Uppsala Monitoring Centre is responsible for the Herbal ATC classification, and it is part of the WHODrug Global portfolio available by subscription.
According to the definition, "[t]he DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults.
"[15] National issues of the ATC classification, such as the German Anatomisch-therapeutisch-chemische Klassifikation mit Tagesdosen, may include additional codes and DDDs not present in the WHO version.
If accepted it becomes a final decision and published semi-annually on the website and WHO Drug Information and implemented in the annual print/on-line ACT/DDD Index on January 1.
[18] Changes to existing ATC/DDD follow a similar process to become temporary codes and if accepted become a final decision as ATC/DDD alterations.
ATC and DDD alterations are only valid and implemented in the coming annual updates; the original codes must continue until the end of the year.