Question about dosage info for combination drugs

Implementers
1

Hello,

I’m currently working on loading drug data into the drug_exposure table and have encountered a challenge with combination drugs.

I have a source record like this:

{
   "fdb_generic_name": "TRIFLURIDINE/TIPIRACIL",
   "treatment_date": "...",
   "duration": 28,
   "duration_type": "day",
   "dose": 55,
   "measure_unit": "mg"
   // other fields...
}

My assumption is that the dosage (55 mg) should help determine the “quantity” field. Based on guidance from this document, I understood that I should first map the drug to its OMOP concept ID.

When I map “TRIFLURIDINE/TIPIRACIL”, I obtain concept id 36029751; however, this concept is non-standard and is linked to two standard OMOP concept IDs corresponding to the individual ingredients “TRIFLURIDINE” and “TIPIRACIL.”

I don’t have any information on how the total 55 mg dose is split between the two ingredients. My question is:

What is the recommended approach in this situation?

Should I:

  • Create two separate drug exposure records (one for each ingredient) and leave the dosage fields null, or
  • Use another strategy to capture the total dose without misrepresenting the exposure details?

Any guidance or best practices on handling such combination drugs in the OMOP CDM would be greatly appreciated.

Thank you!

2

Hello @mr.nim.li

If you don’t know the dose or amount of active drug ingredient for a source record, then you should map it to the standard concept_id of the active ingredient/s.

Also, the two sources for how data should be inserted into the CDM are the CDM v5.4 specification document and the Themis conventions. You can find information about the Drug_Exposure.quantity field in these documents.

3

Hello,

Thank you for your response and for providing the helpful links.

For the combination drug “TRIFLURIDINE/TIPIRACIL,” I can map it to two standard concept IDs:

  • 35602757 (Tipiracil)
  • 905078 (Trifluridine)

After following the links, I reviewed the drug_dose documentation, and specifically Section 5 on “Compounded drugs.” According to this section, determining the value for drug_exposure.quantity may require knowing the proportion (e.g., percentage) of each compound in the drug. However, my source data does not include this proportional information.

It seems that when multiple standard concept IDs are involved, it may not be feasible to accurately populate the drug_exposure.quantity field without knowing the dosage split for each component.

Could you kindly comment on whether my interpretation is correct? Any further guidance on handling dosage information would be appreciated.

Many thanks!

4

Correct, @mr.nim.li

Your interpretation is correct. Based on your source data, you can only accurately map the above data to

5

Thank you for your follow-up. :slightly_smiling_face:

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