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MedDRA Dictionary Introduction:

The Medical Dictionary for Regulatory Activities(MedDRA) is an international multilingual terminology that is applicable through all phases of the development cycle. Use of medDRA on a global basis allows standardized communication between industry and regulators regardless of country or agency. MedDRA permits the classification of a wide range of clinical information and medical syndromes and provides support for multiple medical product areas.

MedDRA is clinically validated International medical terminology used by regulatory authorities and the regulated biopharmaceutical industry.

>> Autumn 1994: Development of MedDRA,under ICH

>> July 1997: ICH approved MedDRA

>> February 1996: Version 1.5 released to scientific community

>> March 1999: First public version was released (Version 2.1)

MedDRA is a Hierarchy of Terms:

MedDRA Hierarchy


Unique Functions of MedDRA:

Multiaxial terminology allows:

  • Terms can be grouped by different classifications
  • Retrieval and presentation via different data sets
  • Automatic assignment of predefined term groupings

Rules that MedDRA terms must follow include:

1. Spelling:

  • British English Speeling for PTs and above. E.g: Oedema NOS
  • American English Spelling at LLT level. E.g: Edema NOS
  • Misspellings are flagged as noncurrent

2. Capitalization: Only the initial letter of the text string is capitalized. E.g: HLGT: Injuries by physical agents.

  • Exceptions: Proper names, components of microorganism taxonomic names, and abbreviations. E.g: HLGT: Lymphomas Hodgkin’s disease

3. Abbreviations/Acronyms: Abbreviations are not punctuated. Generally excluded above the LLT level

  • Exceptions: 1. Well established acronyms and abbreviations. E.g: CDC, ECG.
  • 2. All terms containing more than 100 characters are truncated.

4. Punctuation:Punctuation is not used in the English version. Including diacritical terms. E.g: in Guillain Barre Syndrome, the “e” is not represented.

  • Exceptions: 1. Apostrophes are used in people’s names. E.g: PT: Crohn’s disease
  • 2. Hyphens are included. E.g: PT: Acute pre-renal failure

5. Numeric Values: Numerical values are excluded from MedDRA.

  • Excepions: When the number is medically relevant to the terms.E.g: PT: 17 ketosteroids urine, PT: HIV-2 infection

6. Use of qualifiers: Qualifiers are not used in MedDRA. E.g: rare,frequent.

  • Exception: When a qualifier adds new meaning to a concept E.g: PT: Crohn’s disease vs PT: Crohn’s disease aggravated

7. Gender specific Terms: Gender specific terms are generally not included.

  • Exception: Certain breast and reproductive tract disorders. E.g: PT: Breast neoplasm NOS male

8. Word Order: Generally natural language word order is adopted at the PT level and higher.

  • Exception: Instances where reversal of words in PTs allows similar terms to be grouped together for display in SOC hierarchies for viewing through a relational database.
  • E.g:
     Natural Order MedDRA order
    Aseptic meningitis Meningitis aseptic
    Bacterial meningitis Meningitis bacterial NOS
    Gonococcal meningitis Meningitis gonococcal

9. Legality: Legality issues are excluded from the PT level and above because legal/illegal cannot be defined on an international basis

  • E.g: PT: Abortion induced incomplete complicated
  • LLT: Legally induced abortion , incomplete. Complicated by shock

10. NOS/NEC:

  • NOC(Not Otherwise Specified): Reflects nonspecific commonly used terms
  • NEC(Not Elsewhere Specified): For specific,yet miscellaneous terms that do not readily fit into other hierarchical classificatons

What does a MedDRA code look like?

In MedDRA, a heart attack looks like “10028600”

  • Each MedDRA term is assigned an 8-digit numeric code
  • The code is non-expressive
  • Codes can fulfill a data field in various electronic submission types
  • Initially assigned alphabetically by term starting with 10000001, new terms are assigned sequentially.
  • Supplemental terms are assigned codes

What is Standardised MedDRA Queries?

Standardised MedDRA Queries (SMQs) are tools developed to facilitate retrieval of MedDRA-coded data as a first step in investigating drug safety issues in pharmacovigilance and clinical development. SMQs are validated, pre-determined sets of MedDRA terms grouped together after extensive review, testing, analysis, and expert discussion. SMQs are a unique feature of MedDRA and provide a strong tool to support safety analysis and reporting. The SMQ topics are intended to address the important pharmacovigilance topics needed by regulatory and industry users. SMQs have been developed with the CIOMS Working Group on Standardised MedDRA Queries that provides pharmacovigilance expertise and validation of SMQs. The SMQs are maintained with each release of MedDRA by the MSSO.

Currently, almost 100 SMQs have been created. The following are a small sampling of SMQs that are available to users today:

  • Anaphylactic reaction
  • Cerebrovascular disorders
  • Convulsions
  • Depression and suicide/self-injury
  • Drug abuse, dependence and withdrawal
  • Hyperglycaemia/new onset diabetes mellitus
  • Hypersensitivity
  • Ischaemic heart disease
  • Lack of efficacy/effect
  • Severe cutaneous adverse reactions