The WHO Drug Dictionary (WHO-DD)

The WHO Drug Dictionary is the traditional, practical answer to the product identification problem Lesson 16.1 introduced, and it comes from the same institutional home as several tools this course has already built in depth: it’s maintained by the WHO Collaborating Centre for Drug Statistics Methodology, working alongside the Uppsala Monitoring Centre — the same WHO-UMC behind the causality scale Module 6 built and the VigiBase infrastructure Module 7 covered.

Structurally, WHO-DD links together the different names a single medicine can go by — trade names (the branded product name a specific company markets), generic names (the standardised non-proprietary name for the active substance), and the underlying active ingredient itself — into one coherent, cross-referenced structure. A case reported using any one of these name variants can be traced back to the same underlying substance, which is exactly the linking mechanism that prevents the scattering problem Lesson 16.1 described.

WHO-DD also assigns every drug to the Anatomical Therapeutic Chemical (ATC) classification system, which organises drugs by the organ or system they act on and their therapeutic, pharmacological, and chemical properties. This is worth recognising immediately as the same ATC coding Module 15’s OMOP Common Data Model lesson referenced directly in its Drug Exposure domain — WHO-DD’s ATC assignment is precisely the standard vocabulary that makes OMOP-based drug exposure analysis possible across different databases at all.

WHO-DD has, in practice, been the dominant, widely-adopted standard for drug identification specifically within spontaneous reporting systems worldwide, including VigiBase itself — which is exactly why a working PV professional encounters it constantly in day-to-day case processing, even before the newer IDMP framework (Lesson 16.3) enters the picture as a more structurally rigorous, if less universally implemented, successor.