Guidelines for ATC classification and DDD assignment - WHOCC

2. Data requirements for submission
When requesting changes of DDDs, the data requirements are similar to the data
required for new DDDs. An important basis for the ATC/DDD system is to
maintain a stable database for drug consumption studies. Because of this, there
need to be compelling reasons to change DDDs. Conclusive arguments might be:
- a change in the main indication so that the average dose used has been altered.
- a large change (in the order of 50 %) in the average dose used (see also page 23).
This would need to be supported by detailed market research data in a range of
countries including developing countries. However, for the three year revision a
smaller change can be accepted (see page 29).
Minor changes in DDD for reimbursement, pricing or marketing purposes will not
be considered.
VI. DESCRIPTION OF ATC INDEX WITH DDDs
The WHO Collaborating Centre for Drug Statistics Methodology publishes a new
issue of the complete ATC index with DDDs annually. The complete ATC index
consists of one list sorted according to ATC codes, including all the established
ATC codes and DDDs for plain substances, and one list alphabetically sorted
according to nonproprietary drug names, including all ATC 5th levels. A
searchable version of the index is available on the website www.whocc.no. The
search options enable the user to find ATC codes and DDDs based on substance
name or ATC levels. Text from the Guidelines for ATC classification and DDD
assignment linked to the ATC level is also available. The text will give information
related to the background for the ATC and DDD assignment. The complete ATC
index can also be ordered from the Centre as a paper copy or as an electronic
version. A pdf document of the Guidelines is available on our website.
The DDDs, which are to be reviewed during the year, are marked with an asterisk
in the ATC index.
Lists of the annual ATC/DDD alterations and new ATC/DDDs are available in
December each year on our website www.whocc.no. The lists are distributed free
of charge by email to the users of the ATC/DDD system that are included on the
Centre’s mailing list.
Cumulative lists of ATC/DDD alterations performed since 1982 are available on
our website www.whocc.no.
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