The ATC (Anatomical Therapeutic Chemical classification system) classification system, along with specially developed units of drug consumption - Defined Daily Doses (DDD), has been adopted by WHO as the basis of the international methodology for conducting statistical studies in the field of drug consumption. Currently, the ATC/DDD system is widely used by both government agencies and pharmaceutical companies in many countries around the world.

Drug classification systems serve as a “common language” used to uniformly describe their nomenclature in a country or region, and also allow data on drug consumption to be compared at the national and international levels.

Providing access to standardized and validated information on the use of medicines is necessary for:

Conducting an audit of their consumption structure,
- identifying shortcomings in their use,
- initiation of educational and other events, etc.

The main purpose of creating international standards is to compare data from different countries.

The field of drug consumption research is currently dominated by two systems.

Anatomical Therapeutic (AT) classification developed by the European Pharmaceutical Market Research Association (EPhMRA);

Anatomical Therapeutic Chemical (ATC) classification developed by Norwegian scientists.

The system developed by the EPhMRA classifies medicines into groups of three or four levels. The ATC classification modified and expanded the EPhMRA classification to include therapeutic/pharmacological/chemical subgroups at the fourth level and chemical substances at the fifth level.

The EPhMRA classification is used by IMS to provide statistical market research results for the pharmaceutical industry. It must be emphasized that due to a number of technical differences between the EPhMRA and ATC classification systems, it is not possible to directly compare the data collected using both systems.

The ATC classification system (Anatomical Therapeutic Chemical classification system), along with specially developed units of drug consumption - established daily doses (DDD- Defined Daily Doses) has been adopted by WHO as the basis of an international methodology for conducting statistical studies in the field of drug consumption.

Currently, the ATC/DDD system is widely used by both government agencies and pharmaceutical companies in many countries around the world.

It should be noted that any international standards are born in the search for a compromise, and the drug classification system is no exception to the general rule. Medicines may be used for two or more equally important indications, but the main indications for their use may vary from country to country. This often leads to different alternatives for their classification, but a decision must be made regarding the main indication. Countries with drug uses other than those defined by the ATC system may seek to develop national classification systems. However, it is first necessary to weigh the importance of national traditions, on the one hand, against the possibility of introducing a methodology that will allow reliable comparisons of drug consumption at the international level. Currently, there are many examples that the active implementation of the ATC/DDD methodology has turned out to be a powerful impetus for conducting national research in the field of drug consumption and creating effective drug control systems.

PBX SYSTEM DEVELOPMENT

The prerequisites for the creation of the ATC classification were the emergence of a large number of new drugs in the 50-60s of the 20th century, which led to an increase in the cost of drug treatment. In this regard, the first international studies on drug consumption were carried out in the 60s. Comparison of drug consumption in 6 European countries in 1966-1967. found significant national differences in their use. In 1969, the WHO European Office organized and held a symposium on “Medicine Consumption” in Oslo, where it was decided that it was necessary to develop an international classification system to study the characteristics of drug consumption.

In the early 1970s, the Norwegian Medicines Regulatory Agency (Norsk Medisinaldepot, NMD) used the Anatomical Therapeutic Classification developed by the European Pharmaceutical Market Research Association (EPhMRA) for this purpose. The Agency substantially modified and expanded it, creating the system now known as the ATS classification system. In addition, since strict methodological standards must be applied to obtain reliable information on drug consumption, there has been a need not only for a generally accepted international classification system, but also for a universal unit of measurement of drug consumption. This unit is called the “defined daily dose (DDD).”

In 1981, the WHO Regional Office for Europe recommended the use of the ATC/DDD methodology in other countries of the world.

In 1982, the WHO Collaborating Center for Drug Statistics Methodology was created, which operates on the basis of NMD in Oslo, is a coordinating body and promotes wide international dissemination of the ATC/DDD methodology. In 1996, WHO indicated the need to use the ATC/DDD system as an international standard for drug consumption studies, and the Center came under direct control of WHO headquarters in Geneva.

The responsibilities of the center are:
- classification of new drugs,
- definition of DDD,
- periodic revision of the classification of ATC and DDD.

In 1996, the WHO International Working Group on the Methodology of Statistical Studies of Medicines was created. Its experts, appointed by WHO, are engaged in the further development of the ATC/DDD system, developing guidelines for awarding and changing ATC codes, established daily doses, etc.

STRUCTURE AND NOMENCLATURE OF THE CLASSIFICATION SYSTEM OF ATS

The ATC classification system is a system for dividing drugs into groups depending on their effect on a specific anatomical organ or system, as well as on their chemical, pharmacological and therapeutic properties.

Medicines are classified into 5 different levels.

Level 1 indicates an anatomical organ or organ system and has a letter code:

Each first-level group has subordinate second-level groups.

Level 2 groups have a three-digit alphanumeric code.
Example of second level subgroups for group A:

• A01 Dental preparations;
• A02 Preparations for the treatment of diseases associated with acidity disorders;
• A03 Preparations for the treatment of functional gastrointestinal disorders;
• A04 Antiemetics;
• A05 Preparations for the treatment of diseases of the liver and biliary tract;
  etc.

Level 3 groups have a four-digit code, level 4 groups have a five-digit code.

Below is an example of level 3 and 4 subgroups for group A02:

• A02A Antacids
  • A02AA Magnesium preparations
  • A02AB Aluminum preparations
  • A02AC Calcium preparations
  • A02AD Combination of aluminum, calcium and magnesium preparations
  • A02AF Antacids in combination with carminatives
  • A02AG Antacids in combination with antispasmodics
  • A02AH Antacids in combination with sodium bicarbonate
  • A02AX Antacids in combination with other drugs
• A02B Antiulcer drugs and drugs for the treatment of gastroesophageal reflux
  • A02BA Histamine H2 receptor blockers
  • A02BB Prostaglandins
  • A02BC Proton pump inhibitors
  • A02BD Combinations of drugs for eradication of Helicobacter pylori
  • A02BX Other antiulcer drugs and drugs for the treatment of gastroesophageal reflux

The fifth level of the ATC classification indicates a specific substance. Example of fifth level groups for group A02BA:

• A02BA Histamine H2 receptor blockers
• A02BA01 Cimetidine
• A02BA02 Ranitidine
• A02BA03 Famotidine

A single substance may have 1 or more ATC codes depending on the route of administration, dose and therapeutic use.

Let's look at an example of codes assigned to tetracycline:

And one more example: bromocriptine preparations can be produced in various dosages. Tablets with a low dose of the active substance are used as inhibitors of prolactin synthesis, they are assigned the code G02CB01:

Bromocriptine tablets with greater strength are used to treat parkinsonism and in the ATC classification have code N04BC01:

NOMENCLATURE OF THE PBX SYSTEM

The ATC system uses WHO International Nonproprietary Names (INN) for pharmaceutical substances. If the active substance has not yet been assigned an INN, then other generally accepted non-proprietary names are used, mainly those accepted for use in the United States (United States Adopted Names, USAN) or the UK (British Approved Names, BAN).

CRITERIA FOR INCLUSION OF MEDICINES IN ATC

The WHO Center includes new entries in the ATC classification only at the request of manufacturers, drug regulatory agencies and research institutions. WHO has developed a special procedure for reviewing applications for the introduction of new articles into the ATC classification, which is in many ways similar to the procedure for assigning INNs.

ATS codes are usually not assigned to:

New substances before submitting an application for licensing;

Auxiliary medications.

Combined drugs.

Exception constitute fixed combinations of active substances widely used in a number of countries, for example:

A02BD Combinations of drugs for eradication of Helicobacter pylori

PRINCIPLES OF CLASSIFICATION OF MEDICINES

The fundamental principle is that all medicinal products that have similar ingredients, strengths and dosage forms are assigned only one ATC code.

If a drug is available in different dosage forms with different strengths, composition or therapeutic indications for use, it may have more than one code.

WHO indicates that substances classified in the same level 4 cannot be considered pharmacotherapeutically equivalent, since they may differ in their mechanism of action, therapeutic effect, drug interactions and adverse reactions.

New medicinal substances that do not belong to the known groups of similar substances of the 4th level of the ATC are usually included in group “X” (“other”) of the 4th level. And only if several such substances belong to the same group of level 4, a new group will be created for them at the next revision of the classification. Therefore, innovative drugs are often included in groups with the “X” index.

The system retains obsolete or discontinued drugs and therefore does not guide decision-making on issues such as pricing, generic or therapeutic substitution of drugs, or reimbursement for drug treatment. Assigning an ATC code to a medicinal product also does not constitute a recommendation for its use or an assessment of its effectiveness, including in comparison with other medicinal products.

WHO strives to ensure the stability of ATC codes and daily doses, which is necessary for research.

DDD-Defined Daily Doses

The ATC classification system is closely related to the use of a specially developed unit of measurement for drug consumption - DDD.

The WHO defines the DDD as “the estimated average maintenance daily dose of a medicinal product used for its primary indication in adults.” The DDD is not the same as the recommended daily dose, which may depend significantly on the severity and nature of the disease, the patient's body weight, ethnic origin, recommendations of national drug therapy guidelines and other factors.

For example, WHO guidelines indicate that recommended daily doses in different countries may differ by 4-5 times. The DDD is a fixed measure of actual drug consumption and can be used to conduct comparative studies of drug consumption among different population groups. DDD is determined only for those medicines that have been assigned an ATC code and that are present on the pharmaceutical market in at least one country.

Typically, data on drug consumption are presented as the formula DDD/1000 residents/day, and when estimating consumption in hospitals - DDD/100 bed days.

In the ATC indices published by WHO, in a separate column next to the chemical substance, the method of administration and DDD are indicated (in most cases).

AREAS OF APPLICATION OF THE ATC/DDD METHODOLOGY

1. Collection and analysis of statistical data on the consumption of medicines.

2. Conducting consumption studies medicines on various scales (in individual medical institutions, in the region, in the country, at the international level).

3. Use of the system for educational purposes, in creating information databases about medicines.

4. Assessing the safety of medicines.

5. Analysis of cases of improper prescription or dispensing of drugs.
WITHusing level 5 ATC codes, they analyze data on prescriptions or dispensing of medicines to prevent cases of “duplicate” (simultaneous use by a patient of two medicines with different trade names, but containing the same active substance) and “pseudo-duplicate” (the patient taking two medicines) drugs with different active substances, but having similar pharmacodynamic properties, for example diazepam and oxazepam) drug prescriptions.

6. Creation of Registers of Medicines.

Making changes to the PBX system

The availability of medicines on the market is constantly changing and the volume of their use is increasing, which dictates the need for regular revision of the ATC system. The principle here is of great importance: reduce the number of changes to a minimum. Before making a change, it is necessary to consider and weigh all the difficulties that it will cause for the user of the PBX system and compare them with the benefits that can be achieved due to this change. Changes to the ATC system are made in cases where the main indication for the use of a drug has undoubtedly changed, and when it is necessary to create new groups corresponding to new active substances, or to deepen the differentiation of the group of drugs.

The ATC/DDD methodology is a dynamic system and changes can be made to it continuously (every year WHO publishes a list of changes made to the classification system).

Finally, in almost every country there are single-drug and combination drugs that do not have an ATC code or DDD. In such cases, advice should be sought from the WHO Collaborating Center for Drug Statistics Methodology in Oslo and an application for a new ATC code and DDD should be submitted. Since ATC codes and DDDs are linked to national drug lists, these lists must be regularly updated in accordance with the annual update of the ATC/DDD system.

The full classification index of ATC codes, like the DDD, is usually republished annually by the WHO Collaborating Center for Drug Statistics Methodology.

The latest version of the ATC classification and detailed information about the ATC classification system can be found at http://www.whocc.no/atcddd/

List of information used:

The task of every doctor is not only to assess the patient’s condition and, based on the symptoms, establish the correct diagnosis, but also to correctly determine the medication that will help cope with the disease that has arisen. To quickly find the right drug, an international standard for the methodology of all known medications was created - ATC (ATC). The classification of drugs at the international level is called the "Anatomical Therapeutic Chemical Classification System". The system is based

Purpose of the system

The main purpose of the system is to improve the quality of drug treatment and its availability in different countries. For this purpose, statistics on drug consumption patterns are maintained all over the world, and all research data is accumulated in the ATC system. The classification of medicines is based on the division of medicines according to their active component. All drugs with the same active substance and similar therapeutic effect are assigned one affiliation code.

A medicine may have several codes if it has different release forms with different concentrations of the active component. All medications are divided into groups, which are defined in the code by letters and Arabic numerals. This allows code specialists to determine the identity and therapeutic effect of any medicine registered in the system. The classification of medicinal products (ATC) provides one code for one medicinal product, even if there are equally important indications. The decision on which indication should be considered the main one is made by a WHO working group.

Criteria for inclusion in the system

Manufacturers, research institutions, and drug regulatory agencies apply for drug data entry. The following is the procedure for introducing a new article into the system. Not all drugs are included in the ATC. The classification of drugs does not contain data on combination drugs, with the exception of substances with a fixed combination of active components, such as beta-adrenergic blockers and diuretics. Also, the system does not include traditional medicine aids and unlicensed drugs.

Cautions

Classification of medicinal products (ATC) cannot be considered as a recommendation for use or assessment of the effectiveness of a particular drug. Drug treatment should be prescribed by a specialist.

The ATC classification system (Anatomical Therapeutic Chemical (ATC) classification system) has been adopted by WHO as the international standard methodology for conducting statistical studies of drug consumption in different countries. The ATS system has been developed under the auspices of WHO since 1969. In the early 70s. XX century The Norwegian Medicines Regulatory Agency (Norsk Medisinaldepot, NMD) modified and expanded the Anatomical Therapeutic Classification of the European Pharmaceutical Market Research Association (EPhMRA), creating the system known today as the ATC classification system. ATS issues are dealt with by the coordinating body - the WHO Center for Collaboration in Statistical Research Methodology.

Structure and nomenclature

ATS classification system

In the ATC system, drugs are classified according to their primary therapeutic use (that is, the main active ingredient). The fundamental principle is that only one ATC code is defined for each finished dosage form. A medicinal product may have more than one code if it contains different doses of the active substance or is presented in several dosage forms, the therapeutic indications for which are different. Where a drug has two or more equally important indications or its primary therapeutic use differs from country to country, the WHO Technical Working Group decides which indication should be considered as the primary indication and usually only one code is assigned to that drug. When new drugs are included in the official index of ATC codes, the WHO Center primarily considers simple drugs (containing a single active substance), but fixed combinations of active substances that are widely used in different countries are also assigned ATC codes. Combination drugs whose active ingredients are assigned to a single therapeutic level 4 are usually classified using level 5 codes having series of 20 or 30; combination drugs whose active ingredients do not belong to the same therapeutic group at level 4 are classified using level 5 codes having a series of 50.

We draw the attention of COMPENDIUM readers to the fact that for the convenience of using the reference book, drugs that do not have international codes are divided into several additional groups, marked with the sign “**”. The codes for these groups are not officially approved by WHO and may not coincide with those in other countries.

Principles of classification of vehicles

The WHO Center includes new entries in the ATC classification only upon application (from manufacturers, drug regulatory agencies, research institutions). When including new drugs in the ATC code index, the Center primarily considers simple drugs (containing a single active substance, usually with an INN and well-known properties).

Individual ATS codes are not assigned to:

1. combination drugs (with the exception of widely used fixed combinations of active substances);
2. new substances before submitting an application for licensing;
3. auxiliary drugs or traditional medicine.

Assigning an ATC code to a medicinal product also does not constitute a WHO recommendation for its use or an assessment of its effectiveness, including in comparison with other medicinal products. ATC codes are usually published annually (latest edition - ATC classification index with DDDs, January 2014, WHO Collaborating Center for Drug Statistics Methodology, Oslo, Norway).

In the ATC system, simple drugs are classified according to their primary therapeutic use (by active ingredient). The main principle is that all drugs that have similar ingredients, strength and dosage form are assigned only one ATC code. A medicinal product may have more than one code if it is produced in dosage forms with different strengths, composition or therapeutic indications for use. Different dosage forms for topical or systemic use also have different ATC codes. If a medicinal product has two or more equally important indications, the WHO International Expert Working Group decides which indication is considered the main indication and assigns a single code accordingly.

Innovative medicines that do not belong to the known groups of similar substances of the 4th level of the ATC are temporarily included in group “X” (“other”) of the 4th level. If several such substances are assigned to one group of the 4th level, then at the next revision of the classification a new group is created for them. Therefore, innovative drugs are often included in groups with the “X” index.

Basic principles of classification of combination drugs:

1. combination drugs, the active ingredients of which belong to one level 4, are classified using level 5 codes having a series of 20 or 30 (for example, N01B B02 - lidocaine, N01B B04 - prilocaine, N01B B20 - combinations);
2. combination drugs, the active ingredients of which belong to different groups of level 4, are classified using level 5 codes with a series of 50 (for example R06A A02 - diphenhydramine, R06A A52 - diphenhydramine, combinations); in this case, different combination preparations containing the same main active ingredient will have the same code (for example, phenylpropanolamine + brompheniramine and phenylpropanolamine + cinnarizine have the code R01B A51);
3. combination preparations containing psycholeptics and not classified under codes N05 (psycholeptics) or N06 (psychoanaleptics) are classified using level 5 codes having a series of 70. This also includes other substances of the same level 4 containing psycholeptics.

Advantages of the PBX system:

• allows you to identify the medicinal product, including the active substance, determine the method of its administration and, in appropriate cases (if the DDD is indicated), the daily dose of consumption;
• unlike most other classifications, ATC takes into account both the therapeutic properties of drugs and chemical characteristics;
• has a hierarchical structure, which facilitates the logical division of drugs into certain groups.

ATC codes are included in some international (eg European Medicines Index) and national registries, and WHO recommends that such registries be maintained in every country.

Unifying information shared around the world helps solve common problems faster. Systematized ATC classification of drugs helps to successfully overcome issues related to public health.

Principles and necessity of anatomical - therapeutic - chemical classification of drugs

International classification systems are designed to adapt the information used by different countries. The issue of systematization is especially relevant when it comes to public health. Using the ATC classification of drugs, specialists around the world solve a number of common issues.

Purpose of ATC drug classification

Today, almost every instruction for the medical use of a medicinal product contains the clause “ATC code”. Nearby are Latin letters and numbers. For what purpose and who assigns such a code to a medicine? What is its purpose?

The abbreviation ATC stands for anatomical - therapeutic - chemical systematization of drugs. This classification of medicines is the fruit of the work of international, and mostly European, experts. The World Health Organization has recommended anatomical - therapeutic - chemical systematization of drugs as a unified order since the beginning of the 80s of the last century for use in all countries.

Anatomical - therapeutic - chemical classification of drugs is used by specialists. By systematizing the range of medicines used in different countries, it is possible to assess statistical data in several areas. The structure of consumption of medicines, identification of defects in their prescription, use of systematized information for research and educational purposes is assessed using specific classification codes.

Principle and structure of ATC drug qualification

Since the middle of the last century, significant progress has been observed throughout the world in the development and manufacture of new medicines. The range of medical products has increased exponentially. The moment came when specialists involved in medical practice and pharmaceutical activities realized that a certain compromise and interaction was necessary to control the current situation.

The ATC classification of drugs is based on several principles and rules. First of all, it was proposed to conditionally divide all drugs into groups based on their area of ​​application, pharmacological action, and chemical structure.

An organ system or one anatomical object of the human body is a fundamental factor for assigning a first level letter code. There are 14 such letter designations in the classification structure.

Letter codes A, B, C, D, G, J, L, M, N, P, R, S are assigned depending on the organ or system to which the pharmacological action of the drug is directed. Medicines that affect metabolic processes or digestion, the heart or blood vessels, hematopoiesis, as well as the treatment of pathologies of the urogenital organs, microbial diseases, immunomodulatory or antitumor drugs have different letter codes in the standardized system. Other medicines are designated by the letter V.

Next, using letters and numbers, according to the chemical structure and pharmacological action of the substances, codes are assigned to the drugs. Groups of medicines are divided into five conditional levels. Each level denotes a position in the overall hierarchy of the international system. The international ATC classification uses only non-proprietary international names or common names.

Criteria and procedure for assigning codes

Typically, a medicine is assigned one code number. The exception is situations when the medication is used to treat several pathologies or the scope of application extends to a number of organs or systems. If a drug has a different strength or release form, then different codes are assigned to each type of drug.

Combination drugs do not have a code designation in the ATC system. However, when a combination of several drugs is constantly used by a number of countries, then such a drug is assigned its own code. However, entire groups of drugs in many countries of the world do not have a fixed code. This is due to many reasons.

The World Health Organization is responsible for assigning codes and considering changes in classification. In order for a medicine to receive its code according to the international classification, responsible representatives must submit an application to a specialized center. Any amendments to the international classification can only be made after careful consideration of all the arguments that led to the changes.

Anatomy-therapeutic-chemical systematization, like any other method of standardization, has its advantages and disadvantages. The ATC classification is difficult to use by a wide range of the population, but without it it is impossible to coordinate the actions of specialists at the international level.