Application for DDD

Data requirements
The following information is required when requesting a new DDD:

• Dose ranges and dosing instructions for each indication in the product information approved by one or more major regulatory authorities
• Proposal for a DDD justified by the submitted information.
• Status concerning marketing authorisation.
• Doses used in clinical trials to support marketing if available.
• Market research data on doses used in practice in various countries if such data are available.
• Where the drug is to fit into an existing ATC classification, comparative dosing information should be provided if available.  It is difficult to define therapeutically equivalent doses with the degree of precision often asked for, and the DDDs within therapeutic groups do not necessarily represent therapeutically equivalent doses.

Procedures (to the top)
All new DDDs are assigned on request from the users.  Requests for new DDDs should be addressed to the WHO Collaborating Centre for Drug Statistics Methodology (Application form).  Electronic applications are preferred and applications are free of charge. Any user may in principle propose a new DDD (e.g. health authorities, pharmaceutical manufacturers, researchers and others).  However, as with ATC code assignment, it is the manufacturer who will usually have the best access to the required information.

A DDD will only be assigned for substances which have received an ATC code, or where the ATC code can be assigned simultaneously with the DDD. DDDs are not assigned before marketing is approved in at least one country. 

All new DDDs are discussed and approved by the WHO International Working Group for Drug Statistics Methodology.

The steps in the approval procedure for new DDDs are very similar to the procedure for new ATC codes: 

• The Centre will confirm receipt of the request for a new DDD and give information to those requesting the DDD (the applicant) about the time schedule for discussion at the following Working Group meeting.
• After approval of the minutes of the Working Group meeting, the decision from the meeting concerning the DDD is distributed from the Centre to the applicant.   
• The new DDDs are published on this website (New ATC/DDD and alterations) and in the next issue of the WHO publication: WHO Drug Information.  A deadline is then allowed for interested parties to comment or object to the new DDD. 
• If objections, justified on submitted evidence, are received, the DDD will be discussed again at the following meeting of the Working Group. If the decision is kept, then the decision is considered final after this meeting.  If a new decision is taken by the Working Group, notification of this new DDD is published at our website and in the next issue of the publication WHO Drug Information.  A deadline is then allowed for any interested part to comment or object to the decision. 
• If no objections are received, the new DDD is considered final, and included in the next issue of the ATC classification index.  A list of final DDDs is also published semi-annually at this website (New ATC/DDD and alterations) and in the WHO Drug Information.

Deadlines for applications (to the top)
Deadlines for applications