Guidelines for ATC classification and DDD assignment ... - WHOCC

The WHO Collaborating Centre for International Drug Monitoring (UppsalaMonitoring Centre), Sweden, receives spontaneous reports of suspected adversereactions from national centres (111 official member countries are included in theprogramme, October 2012). Information on all medicinal products appearing inthese reports is stored in a drug register, linked to the reports database. All singleand multiple ingredient preparations are given an ATC code at the substance level,which allows flexible searches comprising different drug categories or groups ofdrugs. The ATC system is also used for the grouping of drugs in outputdocuments.D. "Double medication" and "pseudo-double medication"The ATC classification can be used as a tool for screening of "double"- and"pseudo-double medication".“Double medication" can be defined as using two identical drugs simultaneously(e.g. two different diazepam preparations) whereas "pseudo-double medication"can be defined as using two chemically different substances but with similarpharmacodynamic properties simultaneously (e.g. a diazepam preparation plus anoxazepam preparation).The objective of checking these situations, by using physician or pharmacy patientcomputer records, is to prevent unnecessary medication, which may increase therisk of side effects.In the case of plain preparations, the ATC 5th level codes can be used; while thelevel to which monitoring must be made depends on the ATC group concerned.For combination products the ATC 5th level code is not always sufficient toidentify all active ingredients. It is therefore recommended to connect all ATCcodes given for each of the different active ingredients to each combinedpreparation.E. Drug cataloguesATC codes are included in some international drug catalogues (e.g. the Martindale)and in several national drug catalogues.ATC codes are also included in the WHO Essential Drug List.36