Drugs & Medication

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.

Drugs are divided into different groups according to the organ or system on which they act and/or their therapeutic and chemical characteristics.

Contents 1 Classification 1.1 First level 1.2 Second level 1.3 Third level 1.4 Fourth level 1.5 Fifth level 1.6 Further notes 2 External links

Classification

In the system drugs are classified into groups at 5 different levels:

First level

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
C	Cardiovascular system
D	Dermatologicals
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
M	Musculo-skeletal system
N	Nervous system
P	Antiparasitic products, insecticides and repellents
Q	Veterinary drug
R	Respiratory system
S	Sensory organs
V	Various

Second level

The second level of the code is based on the therapeutic main group and consists of two digits.

Third level

The third level of the code is based on the therapeutic/pharmacological subgroup and consists of one letter.

Fourth level

The fourth level of the code is based on the chemical/therapeutic/pharmacological subgroup and consists of one letter.

Fifth level

The fifth level of the code is based on the chemical substance subgroup and consists of two digits.

Further notes

The actual drug name used is the International Nonproprietary Name (INN) when available.

The ATC/DDD system is the ATC system with the addition of a measure of the assumed average maintenance dose per day for a drug used for its main indication in adults (Defined Daily Doses).

Other ATC classifications are ATCvet (for veterinary medicinal products) and ATC herbal classification (for herbal remedies).

The ATC classification system was based on the Anatomical Classification (AC-system) developed by the European Pharmaceutical Market Research Association (EPhMRA) and the Pharmaceutical Business Intelligence and Research Group (PBIRG).

External links

• WHO Collaborating Centre for Drug Statistics Methodology
• The Anatomical Therapeutic Chemical Classification System with Defined Daily Doses (from WHO)
• New ATC Codes (from WHO)