The Medical Dictionary for Regulatory Activities (MedDRA) is a standardized medical terminology developed by the International Conference on Harmonisation (ICH) for use in the pre- and postmarketing phases of the medicines regulatory process. MedDRA version 2.0, expected to be available in early 1999, is intended to improve data quality, support effective analysis, and facilitate electronic communication of data in regulatory activities. It covers diagnoses, symptoms, adverse drug reactions, therapeutic indications, and other medical information relevant to pharmaceutical regulatory affairs. MedDRA is a hierarchical, multiaxial terminology with five levels, allowing for specificity in data entry and flexibility in data retrieval. It is derived from various sources, including the WHO's adverse reaction terminology, ICD-9, and COSTART. MedDRA is maintained, developed, and distributed by the Maintenance Support Services Organisation (MSSO). It is intended to be the preferred terminology for international electronic regulatory communication and is used in pharmacovigilance, adverse event reporting, and the construction of standard product information. MedDRA does not include definitions of terms, but there is an ongoing initiative to develop them. The scope of MedDRA includes medicinal and biologically derived products, medical devices, and their health effects, but it does not cover drug or device nomenclature, study design, patient demographics, or numerical values. MedDRA is expected to support the long-term maintenance and evolution of the terminology in response to changing user needs.The Medical Dictionary for Regulatory Activities (MedDRA) is a standardized medical terminology developed by the International Conference on Harmonisation (ICH) for use in the pre- and postmarketing phases of the medicines regulatory process. MedDRA version 2.0, expected to be available in early 1999, is intended to improve data quality, support effective analysis, and facilitate electronic communication of data in regulatory activities. It covers diagnoses, symptoms, adverse drug reactions, therapeutic indications, and other medical information relevant to pharmaceutical regulatory affairs. MedDRA is a hierarchical, multiaxial terminology with five levels, allowing for specificity in data entry and flexibility in data retrieval. It is derived from various sources, including the WHO's adverse reaction terminology, ICD-9, and COSTART. MedDRA is maintained, developed, and distributed by the Maintenance Support Services Organisation (MSSO). It is intended to be the preferred terminology for international electronic regulatory communication and is used in pharmacovigilance, adverse event reporting, and the construction of standard product information. MedDRA does not include definitions of terms, but there is an ongoing initiative to develop them. The scope of MedDRA includes medicinal and biologically derived products, medical devices, and their health effects, but it does not cover drug or device nomenclature, study design, patient demographics, or numerical values. MedDRA is expected to support the long-term maintenance and evolution of the terminology in response to changing user needs.