I am finding the terminology to parallel the WHO ICD-10 disease codes (another hugely important resource) but have not studied that in much detail. Working with the browsers takes a bit getting used to and displaying the terminology in multiple languages side-by-side is somewhat unwieldy; it is much more handy in the browsing mode rather than in the search mode which is essentially monolingual.

Here is a brief description of this terminology resource published straight from the source:

MedDRA – the Medical Dictionary for Regulatory Activities – is a medical terminology used to classify adverse event information associated with the use of biopharmaceuticals and other medical products (e.g., medical devices and vaccines). Coding these data to a standard set of MedDRA terms allows health authorities and the biopharmaceutical industry to more readily exchange and analyze data related to the safe use of medical products.

MedDRA was developed by the International Conference on Harmonisation (ICH) and is owned by the International Federation of Pharmaceutical Manufacturers and Associations (IFPMA) acting as trustee for the ICH steering committee.