the annual print/on-line ACT/DDD Index on January 1. Changes to existing ATC/DDD follow a similar process to become temporary codes and if accepted become a final decision as ATC/DDD alterations. ATC and DDD alterations are only valid and implemented in the coming annual updates; the original codes must continue until the end of the year. An updated version of the complete on-line/print ATC index with DDDs is published annually on January 1. See also Classification of Pharmaco-Therapeutic Referrals (CPR) ICD-10 International Classification of Diseases International Classification of Primary Care (ICPC-2) / ICPC-2 PLUS Medical classification Pharmaceutical care Pharmacotherapy RxNorm References External links Quarterly journal providing an overview of topics relating to medicines development and regulation. from EphMRA Anatomical Classification (ATC and NFC) atcd. R script to scrape the ATC data from the WHOCC website; contains link to download entire ATC tree. Drugs Pharmacological classification systems World Health Organization