[ATC and EphMRA classifications: evolution from 1996 to 2003 and comparative analysis].

In their daily practice, health practitioners use one or more pharmacotherapeutic classifications. This diversity of classifications impairs the exchange of drug information, while the use of international or European classifications facilitates this diffusion. The "Hospital National Center of Drugs Information" (CNHIM) has integrated ATC (Anatomical Therapeutic Chemical) and EphMRA (European Pharmaceutical Marketing Research Association) classifications into its "Thériaque" database and has given the ATC official status in France by publishing a French translation. The objective of this article was to analyse the evolution of these two classification systems between 1996 and 2003, and to compare their allocations (of codes) with those for the drugs present in Thériaque in January 2002. The ATC comprises 14 principal groups and five levels of hierarchy, while the EphMRA comprises 16 principal groups and three to four levels. In Thériaque, the ATC is linked to active substances and drugs, and the EphMRA to drugs. Data-processing requests have made it possible to make a comparative analysis. Each year, the two classification systems evolve in terms of addition, suppression, modification and subdivision. Two principal differences are evident in the allocations in Thériaque (class EphMRA K "Hospital solutions" versus class ATC B "Blood and blood forming organ"; class EphMRA T "Diagnostic agents" versus class ATC V "Various"). Classifications evolve in parallel or independently, and although they are closely related to one another, they retain their specificities in terms of structure and uses.