The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. It is controlled by the WHO Collaborating Centre for Drug Statistics Methodology, and was first published in 1976.
The classification system divides drugs into different groups according to the organ or system on which they act and/or their therapeutic and chemical characteristics.
In this system, drugs are classified into groups at 5 different levels:
The first level of the code is based on a letter for the anatomical group and consists of one letter; there are 14 main groups:
|A||Alimentary tract and metabolism|
|B||Blood and blood forming organs|
|G||Genito-urinary system and sex hormones|
|H||Systemic hormonal preparations, excluding sex hormones and insulins|
|J||Anti-infectives for systemic use|
|L||Antineoplastic and immunomodulating agents|
|P||Antiparasitic products, insecticides and repellents|
The second level of the code is based on the therapeutic main group and consists of two digits.
The third level of the code is based on the therapeutic/pharmacological subgroup and consists of one letter.
The fourth level of the code is based on the chemical/therapeutic/pharmacological subgroup and consists of one letter.
The fifth level of the code is based on the chemical substance subgroup and consists of two digits.
- Official ATC website, hosted by the WHO Collaborating Centre for Drug Statistics Methodology