Anatomical Therapeutic Chemical Classification System: Difference between revisions

Latest revision as of 05:02, 19 March 2025

The Anatomical Therapeutic Chemical (ATC) Classification System is a global drug classification system that categorizes pharmaceutical drugs based on their anatomical, therapeutic, pharmacological, and chemical properties. It is maintained by the World Health Organization (WHO) Collaborating Centre for Drug Statistics Methodology (WHOCC) and serves as an essential tool for drug utilization research, facilitating the comparison and analysis of medication usage across different healthcare systems.

Overview[edit]

The ATC system provides a standardized framework for classifying drugs by organizing them into a hierarchical structure. This classification is based on:

The anatomical organ system the drug primarily affects.
The therapeutic purpose for which it is used.
Its pharmacological characteristics and mechanism of action.
Its chemical properties and molecular composition.

A key feature of the ATC system is that different brands containing the same active ingredient and indications are assigned the same code. Similarly, a single ATC code may represent a combination of substances used for a specific indication. For example, acetylsalicylic acid (aspirin) has multiple ATC codes:

ATC code A01AD05 – For use in oral treatments.
ATC code B01AC06 – As a platelet inhibitor.
ATC code N02BA01 – As an analgesic and antipyretic.

Additionally, some ATC codes represent a combination of active ingredients, such as ATC code C09BB04, which designates the combination of perindopril and amlodipine. When these components are used individually, they have separate ATC codes.

History[edit]

The ATC system evolved from earlier pharmaceutical classification models, particularly the Anatomical Classification System, which was initially designed for industry use. In 1971, the European Pharmaceutical Market Research Association (EphMRA) introduced an early version of ATC, which classified drugs into four hierarchical levels. This system was later refined by the WHO, and in 1976, the modern ATC system was officially established with the addition of a fifth level for increased specificity.

Classification[edit]

The ATC system consists of five hierarchical levels that progressively define a drug’s classification:

First Level: Anatomical Main Group[edit]

The first level is represented by a single letter and consists of 14 main anatomical groups:

Code	Description
A	Alimentary tract and metabolism
B	Blood and hematopoietic system
C	Cardiovascular system
D	Dermatologicals
G	Genitourinary system and sex hormones
H	Systemic hormonal therapy, excluding sex hormones and insulins
J	Anti-infective agents for systemic use
L	Antineoplastic and immunomodulating agents
M	Musculoskeletal system
N	Nervous system
P	Antiparasitic products, insecticides, and repellents
R	Respiratory system
S	Sense organs
V	Various drug categories

Second Level: Therapeutic Main Group[edit]

This level, represented by two numbers, classifies drugs based on their therapeutic use. For instance:

ATC code N05 – Psycholeptics (drugs that affect the central nervous system).

Third Level: Pharmacological Subgroup[edit]

Represented by a single letter, this level defines the pharmacological class of drugs. Example:

ATC code N05B – Anxiolytic medications.

Fourth Level: Chemical/Pharmacological Subgroup[edit]

Also represented by a single letter, this level specifies the chemical subgroup of the drug. Example:

ATC code N05BA – Benzodiazepine derivatives.

Fifth Level: Chemical Substance[edit]

This final level, represented by two numbers, identifies the specific active ingredient. Example:

ATC code N05BA01 – Diazepam.

Application and Usage[edit]

The ATC system is widely used for multiple purposes in healthcare, pharmaceutical research, and drug regulation:

Drug utilization studies – Helps track medication use trends and supports pharmacovigilance efforts.
Prescribing guidelines – Assists healthcare professionals in ensuring appropriate drug use based on classifications.
International drug comparison – Enables uniform comparisons of drug usage across different countries and healthcare systems.
Reimbursement policies – Used by health insurance providers and government agencies to standardize drug pricing and reimbursement policies.
Public health research – Supports epidemiological studies related to medication consumption.

Limitations[edit]

While the ATC system is a robust classification model, it has some limitations:

Variability in classification – Some drugs may have multiple ATC codes depending on their use.
Region-specific modifications – Different countries may apply slight modifications to the system for local regulatory purposes.
Complex combinations – Drug combinations may not always be adequately classified under a single ATC code.

External Links[edit]

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-'''The Anatomical Therapeutic Chemical (ATC) Classification System''' is an integral [[drug classification]] system that assigns the [[Medication|active ingredients]] of drugs based on the [[organ (anatomy)|organ]] or [[system]] they target, as well as their [[therapeutic]], [[pharmacological]], and chemical properties. This system is regulated and maintained by the [[World Health Organization]] Collaborating Centre for Drug Statistics Methodology (WHOCC). It was introduced to the world for the first time in 1976.<ref name="history">{{cite web|url=http://www.whocc.no/atc_ddd_methodology/history/|publisher=WHO Collaborating Centre for Drug Statistics Methodology|title=ATC/DDD Methodology: History}}</ref>
+'''The Anatomical Therapeutic Chemical (ATC) Classification System''' is a global [[drug classification]] system that categorizes [[pharmaceutical drugs]] based on their [[anatomical]], [[therapeutic]], [[pharmacological]], and [[chemical]] properties. It is maintained by the [[World Health Organization]] (WHO) Collaborating Centre for Drug Statistics Methodology (WHOCC) and serves as an essential tool for [[drug utilization research]], facilitating the comparison and analysis of medication usage across different healthcare systems.
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 == Overview ==
-The primary intent of the ATC system is to provide a standardized approach to classify drugs. This [[Pharmaceutical code|pharmaceutical coding system]] categorizes medications into different groups based on:
+The ATC system provides a standardized framework for classifying drugs by organizing them into a hierarchical structure. This classification is based on:
+* The '''anatomical organ system''' the drug primarily affects.
+* The '''therapeutic purpose''' for which it is used.
+* Its '''pharmacological characteristics''' and mechanism of action.
+* Its '''chemical properties''' and molecular composition.
-The organ or system they act upon
+A key feature of the ATC system is that different brands containing the same active ingredient and indications are assigned the same code. Similarly, a single ATC code may represent a combination of substances used for a specific indication. For example, [[acetylsalicylic acid]] (aspirin) has multiple ATC codes:
-Their [[medicine|therapeutic]] purpose or characteristics
+* '''[[ATC code A01AD05]]''' – For use in oral treatments.
-Their [[chemical classification|chemical properties]]
+* '''[[ATC code B01AC06]]''' – As a platelet inhibitor.
-What's intriguing about this system is that multiple brands having the same active substance and indications will share the same code. Moreover, a single ATC code can represent a specific pharmaceutically active substance or even a combination of substances in a single indication. For instance, [[acetylsalicylic acid]] (aspirin) has multiple codes: {{ATC|A01|AD05}} for local [[mouth|oral]] treatments, {{ATC|B01|AC06}} as a [[platelet inhibitor]], and {{ATC|N02|BA01}} as an [[analgesic]] and [[antipyretic]]. Similarly, one ATC code can correspond to several active ingredients. The code {{ATC|C09|BB04}}, for example, represents the combination of perindopril and amlodipine. However, when prescribed individually, they have their unique codes as {{ATC|C09|AA04}} and {{ATC|C08|CA01}}, respectively.
+* '''[[ATC code N02BA01]]''' – As an analgesic and antipyretic.
-The structure of the ATC system is strictly hierarchical. Each code has a single parent code, with the exception of the 14 top-tier codes, which do not have any parent code. Importantly, the codes function as semantic identifiers. This means they provide complete lineage information about their hierarchical position.
+Additionally, some ATC codes represent a combination of active ingredients, such as '''[[ATC code C09BB04]]''', which designates the combination of [[perindopril]] and [[amlodipine]]. When these components are used individually, they have separate ATC codes.
-[[File:Մորֆին.png|thumb|Մորֆին]]
 == History ==
-The inception of the ATC system has its roots in the earlier Anatomical Classification System. This system, developed as a tool for the pharmaceutical industry, focused on classifying pharmaceutical products based on their properties rather than their active ingredients.<ref>{{cite web|url=http://www.ephmra.org/user_uploads/who-atc%202013%20final.pdf|title=Comparison of the WHO ATC Classification & EphMRA/Intellus Anatomical Classification|publisher=EphMRA|accessdate=7 January 2017|archive-url=https://web.archive.org/web/20150806235351/http://www.ephmra.org/user_uploads/who-atc%202013%20final.pdf|archive-date=6 August 2015|url-status=dead}}</ref> This previous system, also termed ATC, was initiated in 1971 by the [[European Pharmaceutical Market Research Association]] (EphMRA). Maintained by EphMRA and Intellus, its classification involved four levels of hierarchy.<ref>{{cite web|url=http://www.ephmra.org/user_uploads/atcguidelines2016final.pdf|title=EphMRA Anatomical Classification Guidelines 2018|access-date=2017-01-07|archive-url=https://web.archive.org/web/20160423224519/http://www.ephmra.org/user_uploads/atcguidelines2016final.pdf|archive-date=2016-04-23|url-status=dead}}</ref> The modern ATC system, established by WHO, enhanced and modified this structure, adding a fifth level of classification. It was formally published in 1976.<ref name="history"/>
+The ATC system evolved from earlier pharmaceutical classification models, particularly the Anatomical Classification System, which was initially designed for industry use. In 1971, the [[European Pharmaceutical Market Research Association]] (EphMRA) introduced an early version of ATC, which classified drugs into four hierarchical levels. This system was later refined by the WHO, and in 1976, the modern ATC system was officially established with the addition of a fifth level for increased specificity.
 == Classification ==
-The ATC system breaks down drugs into five distinct levels of classification:<ref>{{cite web|url=http://www.whocc.no/atc/structure_and_principles/|publisher=WHO Collaborating Centre for Drug Statistics Methodology|title=ATC: Structure and principles}}</ref>
+The ATC system consists of five hierarchical levels that progressively define a drug’s classification:
-=== First level ===
+=== First Level: Anatomical Main Group ===
-Representing the anatomical main group, the first level comprises one letter. There are 14 primary groups in total:<ref>{{cite web|url=http://www.whocc.no/atc_ddd_index/|publisher=WHO Collaborating Centre for Drug Statistics Methodology|title=ATC/DDD Index}}</ref>
+The first level is represented by a single letter and consists of 14 main anatomical groups:
 {| class="wikitable"
 |-
-!Code
+! Code !! Description
-!Contents
 |-
-| '''[[ATC code A|A]]'''
+| '''[[ATC code A|A]]''' || [[Alimentary tract]] and [[metabolism]]
-| [[Alimentary tract]] and [[metabolism]]
 |-
-| '''[[ATC code B|B]]'''
+| '''[[ATC code B|B]]''' || [[Blood]] and [[hematopoietic system]]
-| [[Blood]] and [[haematopoiesis|blood forming organs]]
 |-
-| '''[[ATC code C|C]]'''
+| '''[[ATC code C|C]]''' || [[Cardiovascular system]]
-| [[Cardiovascular system]]
 |-
-| '''[[ATC code D|D]]'''
+| '''[[ATC code D|D]]''' || [[Dermatologicals]]
-| [[Dermatological]]s
 |-
-| '''[[ATC code G|G]]'''
+| '''[[ATC code G|G]]''' || [[Genitourinary system]] and [[sex hormones]]
-| [[Genito-urinary system]] and [[sex hormone]]s
 |-
-| '''[[ATC code H|H]]'''
+| '''[[ATC code H|H]]''' || Systemic [[hormonal therapy]], excluding sex hormones and insulins
-| Systemic [[Hormone|hormonal]] preparations, excluding sex hormones and insulins
 |-
-| '''[[ATC code J|J]]'''
+| '''[[ATC code J|J]]''' || [[Anti-infective agents]] for systemic use
-| [[Antiinfective]]s for systemic use
 |-
-| '''[[ATC code L|L]]'''
+| '''[[ATC code L|L]]''' || [[Antineoplastic]] and [[immunomodulating agents]]
-| [[Antineoplastic]] and [[immunomodulator|immunomodulating]] agents
 |-
-| '''[[ATC code M|M]]'''
+| '''[[ATC code M|M]]''' || [[Musculoskeletal system]]
-| [[Musculo-skeletal system]]
 |-
-| '''[[ATC code N|N]]'''
+| '''[[ATC code N|N]]''' || [[Nervous system]]
-| [[Nervous system]]
 |-
-| '''[[ATC code P|P]]'''
+| '''[[ATC code P|P]]''' || [[Antiparasitic]] products, [[insecticides]], and [[repellents]]
-| [[Antiparasitic]] products, [[insecticide]]s, and [[insect repellent|repellents]]
 |-
-| '''[[ATC code R|R]]'''
+| '''[[ATC code R|R]]''' || [[Respiratory system]]
-| [[Respiratory system]]
 |-
-| '''[[ATC code S|S]]'''
+| '''[[ATC code S|S]]''' || [[Sense organs]]
-| [[Sense organ]]s
 |-
-| '''[[ATC code V|V]]'''
+| '''[[ATC code V|V]]''' || Various drug categories
-| Various
 |}
-=== Second level ===
-This level, represented by two numbers, showcases the therapeutic main group. For instance, ''ATC code N05'' stands for psycholeptics.
-=== Third level ===
+=== Second Level: Therapeutic Main Group ===
-At the third level, represented by one letter, the therapeutic/pharmacological subgroup is highlighted. Taking ''ATC code N05B'' as an example, it encompasses anxiolytics.
+This level, represented by two numbers, classifies drugs based on their therapeutic use. For instance:
+* '''ATC code N05''' – Psycholeptics (drugs that affect the central nervous system).
+=== Third Level: Pharmacological Subgroup ===
+Represented by a single letter, this level defines the pharmacological class of drugs. Example:
+* '''ATC code N05B''' – [[Anxiolytic]] medications.
-=== Fourth level ===
+=== Fourth Level: Chemical/Pharmacological Subgroup ===
-The chemical/therapeutic/pharmacological subgroup is denoted at this level, which is also represented by a single letter. ''ATC code N05BA'' pertains to benzodiazepine derivatives.
+Also represented by a single letter, this level specifies the chemical subgroup of the drug. Example:
+* '''ATC code N05BA''' – [[Benzodiazepine]] derivatives.
-=== Fifth level ===
+=== Fifth Level: Chemical Substance ===
-This final level, represented by two numbers, specifies the chemical substance. For instance, ''ATC code N05BA01'' designates diazepam.
+This final level, represented by two numbers, identifies the specific active ingredient. Example:
+* '''ATC code N05BA01''' – [[Diazepam]].
-== Usage ==
+== Application and Usage ==
-Given the comprehensiveness and universal applicability of the ATC system, it is extensively employed for drug utilization research. This ensures that prescriptions and drug consumption statistics can be compared and analyzed across countries, facilitating a more precise understanding of drug use patterns.
+The ATC system is widely used for multiple purposes in [[healthcare]], [[pharmaceutical research]], and [[drug regulation]]:
+* '''Drug utilization studies''' – Helps track medication use trends and supports [[pharmacovigilance]] efforts.
+* '''Prescribing guidelines''' – Assists [[healthcare professionals]] in ensuring appropriate drug use based on classifications.
+* '''International drug comparison''' – Enables uniform comparisons of drug usage across different countries and healthcare systems.
+* '''Reimbursement policies''' – Used by [[health insurance]] providers and government agencies to standardize [[drug pricing]] and reimbursement policies.
+* '''Public health research''' – Supports epidemiological studies related to medication consumption.
-Moreover, its hierarchical structure allows for data aggregation at different levels. This means researchers can focus on broader drug categories, like all cardiovascular drugs, or drill down to specific active ingredients.
+== Limitations ==
+While the ATC system is a robust classification model, it has some limitations:
+* '''Variability in classification''' – Some drugs may have multiple ATC codes depending on their use.
+* '''Region-specific modifications''' – Different countries may apply slight modifications to the system for local regulatory purposes.
+* '''Complex combinations''' – Drug combinations may not always be adequately classified under a single ATC code.
-== References ==
+== See Also ==
-<references />
+* '''[[World Health Organization]]'''
+* '''[[Pharmacovigilance]]'''
+* '''[[Drug utilization research]]'''
+* '''[[International drug nomenclature]]'''
+* '''[[Essential medicines]]'''
-== External links ==
+== External Links ==
-* [http://www.whocc.no/ World Health Organization Collaborating Centre for Drug Statistics Methodology]
+* [http://www.whocc.no/ WHO Collaborating Centre for Drug Statistics Methodology]
-{{stub}}
+* [https://www.who.int/publications/m/item/atc-ddd-index WHO ATC/DDD Index]
-{{Major Drug Groups}}
+* [https://www.ema.europa.eu/en European Medicines Agency]
 {{Medical classification}}
-{{Portal bar|Pharmacy and pharmacology}}
+{{Pharmacology}}
+{{DEFAULTSORT:ATC Classification System}}
 [[Category:Drugs]]
-[[Category:ATC codes| ]]
+[[Category:ATC codes]]
-[[Category:Drugs by target organ system| ]]
+[[Category:Drug classification systems]]
+[[Category:World Health Organization]]
 [[Category:Pharmacological classification systems]]
-[[Category:World Health Organization]]