Anatomical Therapeutic Chemical Classification System

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.

Classification

In this 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
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.

External links

• Official ATC website, hosted by the WHO Collaborating Centre for Drug Statistics Methodology
• ATC

Major Drug Groups
Gastrointestinal tract (A)	Antacids • Antiemetics  • H2 antagonists • Proton pump inhibitors • Laxatives • Antidiarrhoeals
Blood and blood forming organs (B)	Anticoagulants • Antiplatelets • Thrombolytics
Cardiovascular system (C)	Antiarrhythmics • Antihypertensives • Diuretics • Vasodilators • Antianginals • Beta blockers • Angiotensin converting enzyme inhibitors • Antihyperlipidemics
Skin (D)	Emollients - Antipruritics
Reproductive system (G)	Hormonal contraception • Fertility agents • Selective estrogen receptor modulators • Sex hormones
Endocrine system (H)	Anti-diabetics • Corticosteroids • Sex hormones • Thyroid hormones
Infections and Infestations (J, P)	Antibiotics • Antivirals • Vaccines • Antifungals • Antiprotozoals • Anthelmintics
Malignant and Immune disease (L)	Anticancer agents • Immunostimulators • Immunosuppressants
Muscles, Bones, and Joints (M)	Anabolic steroids • Anti-inflammatories • Antirheumatics • Corticosteroids • Muscle relaxants
Brain and Nervous system (N)	Anesthetics • Analgesics • Anticonvulsants • Mood stabilizers  • Anxiolytics • Antipsychotics • Antidepressants • Nervous system stimulants • Sedatives
Respiratory system (R)	Bronchodilators • Decongestants  • H1 antagonists