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Adding RxNorm Precise Ingredients as Standard Concepts for Drug_Exposure


(Michael Kahn) #1

Attached below are two valid research use cases from Katy Trinkley Pharm D to justify the inclusion of Precise Ingredients RxNorm codes as allowed standard concepts. What is the official process for moving the request forward?
Michael Kahn

Subject: Clinically meaningful salt forms - RxNorm precise ingredients

Here is some verbiage describing drugs with clinically distinguishable salt forms -

  1. Metoprolol succinate versus metoprolol tartrate are clinically distinct medications. Both can be used to treat a variety of conditions, but only succinate is recommended to prevent complications associated with heart failure and reduced ejection fraction (e.g., prevent hospitalization, prolong survival, improve symptoms). This is explicitly stated in the guidelines.

  2. Isosorbide mononitrate versus isosorbide dinitrate is another example, but potentially less clear. Dinitrate is rarely used in clinical practice because it has poor/inconsistent bioavailability. Dinitrate’s bioavailability is 10-90%, averaging 25% versus nearly 100% with mononitrate.


(Anna Ostropolets) #2

RxNorm moves Ingredients to Precise Ingredients whenever they don’t feel that distinguishing them have practical meaning or they can’t distinguish them clearly in the drug products they have in the ontology. There are two option to proceed:

  1. you submit the request with clinical background + examples of US drugs that contain those specific precise ingredients to Vocabulary v5.0 GitHub and we submit it to RxNorm and wait for their decision
  2. We create such ingredients in RxNorm Extension (probably won’t influence US drugs)

(Michael Kahn) #3

@aostropolets: Thanks for reply. In the current instances, the Precise Ingredients exist as valid RxNorm codes. But OHDSI does not assign them as standard codes. So the issue is within OHDSI, not RxNorm.

Also, I think you wrote your first sentence backwards. Wouldn’t RxNorm only move Ingredients to Precise Ingredients whenever they DO feel that distinguishing them has practical meaning?


(Anna Ostropolets) #4

I can see them in OMOP: https://athena.ohdsi.org/search-terms/terms?conceptClass=Precise+Ingredient&page=1&pageSize=15&query=Metoprolol. They are non-standard as they are not used as ingredients in Rxnorm hierarchy.
And yes, they do NOT distinguish the drugs based on precise ingredients. That’s why, for example, Dutoprol has simple metoprolol as can ingredient and not metoprolol succinate (and both M succinate and tartrate as precise ingredients, which seems to be a mistake).


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