So, just to make sure I understand fully, the strength of the medication will be stored in the drug strength table (not the drug exposure table).
No. That is not correct. The strength of the medication is stored in concept_id filed in Drug_Exposure table. For example, concept_id 21151336 contains the strength information 100 MG/per bottle or per pre-filled syringe. Of course, you get that information from the concept_name column in the Concept table.
And, for a standard concept such as 21151336, there would be a corresponding entry in the derived drug strength table.
Yes. But please note that Drug_Strength table is a derived table from the Drug_Exposure and vocabulary tables. In another word, if the information does not exist in Drug_Exposure table, it will not be in the Drug_Strength table either.
But, how would you suggest we go about mapping an example like ´REMSIMA 150mg´?
In this case, there is no corresponding concept in the vocabulary that has the strength of 150 mg/per bottle REMSIMA. If you are sure that the drug comes with this strength, the best practice is to to ask @Dymshyts to create a new concept with this strength (150 mg). As a alternative, you can certainly map it to the ingredient level as you suggested that has no strength information.