And here I am again, re-opening this conversation. As @Rijnbeek is leading efforts in Europe to map the European drug codes (every European country has its own system), and others around the world are pushing to get their data in the CDM, I notice the drug mapping process has become a major bottleneck.
Again, I think the solution proposed by @Christian_Reich, giving each drug its own concept ID which encodes its ingredient(s), strength, formulation, brand, etc., is a really elegant one. However, I see evidence that it simply doesn't scale. The vast majority of non-US coding systems still don't have complete mapping due to the lack of standard concepts to map to. Just one example is the CPRD database, which has been around a long time and was one of the first to be mapped to the CDM. As of today, still 10% of drug exposures in CPRD are mapped to the ingredient level, including 'Clopidogrel 75mg tablets', simply because that concept isn't a standard in the vocab.
I would again like to put my original proposal on the table: the drug_exposure table should have fields for the ingredient, strength, formulation, and brand. We can have a separate field that links multi-ingredient products. This will greatly simplify the drug mapping process, and actually make life easier on the analytics side as well.