ATCkoodit

ATCkoodit, or ATC codes, refer to the Anatomical Therapeutic Chemical classification system used to categorize medicines and other pharmaceutical substances. The system is maintained by the WHO Collaborating Centre for Drug Statistics Methodology and is widely adopted in national health registries, regulatory agencies, and research settings. It provides a standardized language for describing what a drug is used for and how it acts, facilitating comparability across countries and over time. ATC codes are often used together with Defined Daily Dose (DDD) measurements to quantify drug consumption in populations.

The ATC system is hierarchical and consists of five levels, forming a five-part code. Level 1 denotes the anatomical main group, indicated by a single letter. Level 2, the therapeutic main group, uses two digits. Level 3, the pharmacological subgroup, uses a single letter. Level 4, the chemical subgroup, uses a single additional letter. Level 5, the chemical substance, completes the code with two digits. A complete ATC code thus uniquely identifies a chemical substance and its principal therapeutic use within the system.

Purpose and applications are wide-ranging. Researchers use ATCkoodit to classify medications in epidemiological studies, pharmacovigilance, and health technology assessments. Regulators and payers rely on ATC codes for drug listing and reimbursement decisions, while hospital and population health databases use them to organize and compare drug data across settings and time. The ATC system is updated regularly to reflect new substances and evolving therapeutic practices.