MedDRA 29.1: key changes and operational implications

The MedDRA 29.1 update introduces changes relevant to pharmacovigilance data coding and analysis. Key developments include the revision of certain LLT–PT mappings introduced in Version 29.0, updates to existing SMQs and changes to the currency status of selected terms. This article examines the main changes and their implications for the use of safety databases.

Released in September 2026, MedDRA 29.1 is a simple change version, meaning that changes are limited to the Preferred Term (PT) and Lowest Level Term (LLT) levels. The higher levels of the terminology hierarchy remain unchanged. This classification describes the type of changes introduced, which may nevertheless have implications for data coding and analysis.

For a detailed explanation of the terminology hierarchy and its applications, see our guide to MedDRA and its role in pharmacovigilance.

According to the official What’s New – MedDRA Version 29.1 document, 1,065 change requests were processed, of which 753 were approved and implemented. Compared with Version 29.0, the total number of PTs increased from 27,361 to 27,504 (+143), while the number of records in the LLT file increased from 91,082 to 91,499 (+417). The latter count also includes PTs, which are included in the LLT distribution file.

Understanding the operational relevance of the update requires looking beyond these figures and examining changes to term mappings and their potential implications for coding and safety data analysis.

One of the most significant developments in Version 29.1 concerns the revision of certain LLT–PT mappings related to medication errors.

In MedDRA Version 29.0, several LLTs were moved from PTs relating to “errors” to PTs relating to “issues”, following requests from MedDRA users.

Following a detailed review by a group of medication error experts from industry and regulatory agencies across ICH regions, these changes were reversed in Version 29.1.

The expert group determined that the concepts reviewed, including terms containing the word “wrong”, should be considered errors when reported in Individual Case Safety Reports (ICSRs). This interpretation was also supported by an analysis of how these terms had been used in previously coded cases.

Two examples from the official MSSO document illustrate the changes:

• LLT “Drug maladministration” has been moved from PT “Product administration issue” to PT “Product administration error”.
• LLT “Drug stored in wrong location” has been moved from PT “Product storage issue” to PT “Product storage error”.

For pharmacovigilance professionals, this distinction is relevant: the same LLT may be associated with different PTs depending on the MedDRA version used.

Consequently, cases coded using MedDRA 29.0 with these LLTs may be associated with “issue” PTs, whereas in Version 29.1 the same terms are mapped to “error” PTs. This difference may affect case aggregation and comparisons between analyses performed using different terminology versions. The actual impact on historical data depends on the versioning and recoding procedures adopted.

The review of this area is still ongoing. The MSSO and the ICH M1 Points to Consider Working Group are reviewing the HLGT “Medication errors and other product use errors and issues”. Further changes to medication error and issue terms, as well as new or revised concept descriptions, may therefore be introduced to clarify term interpretation.

MedDRA 29.1 introduces 13 LLT currency status changes: 12 terms have become non-current and one has become current.

Non-current LLTs remain in the terminology to preserve historical data and support their retrieval and analysis. According to the ICH guidance on MedDRA Term Selection: Points to Consider, Section 2.5, these terms should not be used for new coding.

The changes include the LLTs “Paracetamol”, “Acetaminophen” and “Salicylate”, which have been made non-current because drug names as such are outside the scope of MedDRA. To represent the corresponding drug level concepts, the LLTs “Paracetamol drug level”, “Acetaminophen drug level” and “Salicylate drug level” have been added under PT “Analgesic drug level”.

Other changes concern terms considered ambiguous or imprecise. For example:

• “Congenital intrahepatic shunt” has become non-current, and the more specific PT “Congenital intrahepatic portosystemic shunt” has been introduced.
• “Walking aid support” has become non-current, and the LLT “Therapeutic use of walking aid” has been added under PT “Mobility support”.

Conversely, LLT “Coloboma of optic disc” has become current, following recognition of the term as a valid clinical concept.

For professionals involved in pharmacovigilance case coding, these changes highlight the importance of distinguishing between the presence of a term in the terminology and its suitability for new coding. Term selection should take into account the LLT currency status and the clinical information reported in the case.

MedDRA 29.1 introduces no new Standardised MedDRA Queries (SMQs) but includes 177 approved PT changes to existing SMQs.

SMQs are predefined sets of MedDRA terms used to identify cases potentially associated with specific medical conditions or areas of medical interest, supporting safety data retrieval and analysis.

Changes to terms included in SMQs may affect case retrieval and, consequently, query results. This is particularly relevant when comparing analyses performed at different points in time.

Even when the same search criteria are applied, using different SMQ versions may contribute to differences in the results obtained. The terminology version used is therefore an important factor when interpreting and comparing safety analyses.

This topic is also addressed in the ICH guidance MedDRA Data Retrieval and Presentation: Points to Consider.

To identify the changes introduced in Version 29.1, including those affecting SMQs, users can consult the MedDRA Version Report, included in the official release package, or use the MedDRA Version Analysis Tool (MVAT).

For comparisons between Versions 29.0 and 29.1, both resources provide identical information. MVAT also allows users to compare non-consecutive versions. Both are available to MedDRA subscribers.

On 17 September 2026, the MSSO released an updated English MedDRA 29.1 package to resolve a loading issue affecting three pairs of LLTs related to Rh antigens, distinguished only by the uppercase or lowercase letter “E”.

The terms were revised to include the corresponding International Society of Blood Transfusion (ISBT) antigen symbols, ensuring that they remain distinguishable in systems that do not support case sensitivity.

The correction affects only the English LLT.asc file and the MedDRA Version Report. Translations released on 15 September are not affected.

From 2 November 2026, MedDRA 29.1 becomes the global version, as confirmed in the official MSSO communication on the updated release.

The update needs to be correctly implemented within the safety database to maintain consistency across coding, SMQs, aggregate analyses and regulatory reporting processes. The approach to managing historical data depends on the versioning strategy adopted.

As with previous releases, Max Application installs MedDRA 29.1 free of charge in its customers’ SafetyDrugs databases and continues to provide the service for loading new versions, allowing users to work with up-to-date terminology consistent with the official release.