A subscription-based product of the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), MedDRA or Medical Dictionary for Regulatory Activities is a clinically validated international medical terminology dictionary-thesaurus used by regulatory authorities and the biopharmaceutical industry during the regulatory process, from pre-marketing (clinical research phase 0 to phase 3) to post-marketing activities (pharmacovigilance or clinical research phase 4), and for safety information data entry, retrieval, evaluation, and presentation. Also, it is the adverse event classification dictionary.
The first version of MedDRA was released in 1999 in English and Japanese.
MedDRA is now translated into Chinese, Czech, Dutch, French, German, Hungarian, Italian, Korean, Portuguese, Brazilian Portuguese, Russian, and Spanish. In MedDRA version 25.0, Swedish and Latvian translations were also added.
In many countries/regions the use of MedDRA by biopharmaceutical companies is mandated for safety reporting. Many other industries, including tobacco and cosmetics, are also beginning to use MedDRA for capturing adverse health events.
All Regulatory Members of ICH are expected to implement MedDRA within 5 years.
As of 2020, the following ICH Regulatory Members have implemented MedDRA: EC, Europe; FDA, United States; HSA, Singapore; Health Canada, Canada; MHLW/PMDA, Japan; Swissmedic, Switzerland; and TFDA, Taipei.
Information about the implementation status of MedDRA by ICH Regulatory Members is updated by ICH on its website.
MedDRA is widely used internationally, with close to 7,500 subscribing organizations in almost 130 countries. Each organization, regardless of its number of users, requires only one subscription to MedDRA.
MedDRA Vision
In developing and continuously maintaining MedDRA, ICH endeavours to facilitate the exchange of clinical information through a single standardized international medical terminology that can be used for regulatory communication and evaluation of data pertaining to medicinal products for human use. As a result, MedDRA is designed for use in the registration, documentation, and safety monitoring of medicinal products through all phases of the development life cycle. The single standardized terminology offers several clear advantages for regulators, industry, and other stakeholders:
Removal of the need to convert data from one terminology to another preventing the loss and/or distortion of data and allowing savings in resources;
Improvements in the ease, quality, and timeliness of data available for effective analysis, exchange, and decision making;
Consistency of the terminology throughout the different stages of the development of a medicinal product allowing effective cross-references and analysis of data;
Facilitation of the electronic exchange of data relating to medicinal products.
Organization of the dictionary
The MedDRA dictionary is organized with a five-level hierarchy. The highest or broadest level is System Organ Class (SOC), further divided into High-Level Group Terms (HLGT), High-Level Terms (HLT), Preferred Terms (PT), and finally into the most granular Lowest Level Terms (LLT). In addition, the MedDRA dictionary includes Standardized MedDRA Queries (SMQs). SMQs are groupings of terms that relate to a defined medical condition or area of interest.
SMQs are developed to facilitate retrieval of MedDRA-coded data as a first step in investigating drug safety issues in pharmacovigilance and clinical development.
As of MedDRA 25.1, 110 SMQs have been created comprising 120 lower-level SMQs. Additional SMQs are created as the need arises.
Individual cases are usually coded for data entry at the most specific (LLT) level, and outputs of counts or cases are usually provided at the PT level. The higher levels (HLT, HLGT, and SOC), as well as SMQs, are used for searching and for organizing and subtotalling outputs.
MedDRA hierarchy
The five-level hierarchy provides degrees or levels of super-ordination and subordination. The superordinate term is a broad grouping term applicable to each subordinate descriptor linked to it. Hierarchical levels thus represent vertical links in the terminology.
Hierarchies are an important mechanism for flexible data retrieval and for the clear presentation of data. The five-level structure of this terminology provides options for retrieving data by specific or broad groupings, according to the level of specificity required. The Lowest Level Term (LLT) level provides maximum specificity.