Drug order - drug formulation required?

In the data model for the drug order table, there is a drug_inventory_id which I believe maps to a row in the drug table. Drugs in the drug table are mapped to a drug and a formulation. For example, paracetamol 500 mg.

When we create a drug order, it seems like we are required to use an entry from the drug table. However this is contrary to my experiences ordering medication in other emrs. In general, as the prescriber, I will prescribe paratecamol 1000 mg q6 hours as needed. I will not have to write paracetamol 500 mg x 2 tabs q5 hours as needed. The pharmacist will receive the order and then choose how to dispense, is it 2 500 mg tabs, or 4 250 mg tabs, etc.

Would appreciate it if someone could clarify if the above understanding is correct.

If this is correct, why did we so tightly link the drug order to the formulation? I’m sure there are good reasons.

If this is the case (tight coupling), is there a way of handling this better (UI, some mapping table of amounts prescribed to quantities of tabs, etc.) so that clinicians are not required to do the math of calculating the number of pills for a given dose? Although this seems trivial in this use case, it becomes more relevant in more complicated dosing schemes as for chemotherapy regimens.



@gschmidt, @rtanui, @nkimaina, @burke

The drug_inventory_id field is nullable. Can you share where it is required?

@dkayiwa, perhaps it’s not required. I guess alternatively, if you don’t provide a drug uuid, you need to include a number of fields which would otherwise have been inferred from the drug table. Is that correct?

Additionally, we would still be interest to know if anyone has come up with a way to represent common orders which could be included in an order set. For example, we might create a Hypertension orderset and include: amlodipine 5 mg daily, amlodipine 10 mg daily, HCTZ 12.5 mg daily, HCTZ 25 mg daily, etc.

We could then use that orderset to populate the UI with recommended drug orders for clinicians seeing patients in the Hypertension clinic.

I suppose one could use the drug table and populate it with common orders. However, my sense was that the drug table was suppose to serve as a formulary, that is, a list of pills actually available in the pharmacy, and not as a way of representing common orders. Would love to hear others thoughts on this.



I’ve just spoken to @burke. He recommends against representing the knowledge of common prescription patterns within ordersets. Instead these should be used for representing complex ordering patterns. Instead, Burke recommending seeing if there was a standard way of representing the knowledge of common ordering instructions perhaps in RxNorm. @jteich and @akanter, do either of you know of a standardized approach to representing this data? My team would then be willing to create this as a module in OpenMRS.



Unfortunately, I don’t think there is a knowledge/dictionary based way of doing this. RxNorm does include specific formulations and strengths, but not the full sig. NCPDP has standards for electronic prescribing and perhaps there is some form of this that could be stored in the drug table… but perhaps Jonathan, you have some ideas?