MeDRA (Medical Dictionary for Regulatory Activities) is an internationally used medical dictionary developed by the ICH in the 1990s which will be widely utilized during pharmaceutical regulatory processes. One of its scopes of use is the data coding of adverse events and adverse reactions. MedRA has been translated into English, Japanese, Czech, Dutch, French, German, Hungarian, Italian, Portuguese and Spanish.
The great advantage of MedDRA is that it organises adverse events reported by clinical investigators into a standard format, making it possible to discover groups and relationships between cases that seem unique at first. This can be used for statistical reporting purposes during the creation of tables and listings. MedRA is structured into various hierarchical groups, arranged from very specific to very general. Based on its hierarcy, a specific event is listed under various connecting groups. The hierarchical groups are as follows:
Among the groups, SOC (System Organ Classes) includes the most general terms, while LLT (Lowest Level Terms) describe fully specific events. Beyond the scope of a given analysis, MedRA has contributed to the standardization of medical databases and hence to a better assessment of diseases.