Canadian Clinical Drug Data Set: Questions on Using DINs

1) I would agree, but with the provincial rules for interchangeability the prescription does not always have to be filled for the same DIN. A pharmacist could change the DIN used on subsequent fills without needing to involve the prescriber.
2) If a prescription is written requesting supply of “Exotowonder® 250 mg capsules [Fred’s Pharma Inc]”, the pharmacist is allowed to dispense “Exotowonder® 250 mg capsules [Joe’s Meds Inc]” without contacting the prescriber, as long as the two products are interchangeable according to their provincial guidelines. The manufacturer/supplier name is considered to be part of the “medicine name” but it is not critical. As long as I knew a patient was taking Extowonder 250mg the brand is not important. The only time it would be is in the case of a brand specific sensitivity due to an excipient difference, or a recall.
3) If a DIN is stored in a record (e.g. in an EHR or DIS) it identifies the product specifically, but again it is the drug and strength that is more important for the clinician to know. As long as they knew it was atenolol 50mg, the difference between Apo-Atenol, PMS-Atenolol etc is not really important. The DIN is used for product verification and checking at the time of dispensing, but for clinical decisions the drug and strength are the critical pieces, unless there is a brand specific sensitivity or recall as in #2.
4) There is little value of manufacturer/supplier in a product name from a clinical perspective. I agree that it differentiates between products when there is no branding of any sort in the name (e.g. if only the INN is used), but does come into play for recalls or brand specific sensitivities.
The only concern would be for products that don't clearly identify the drug, such as Novamoxin, Novatenol, Novamilor etc. There still is the chemical name, but you can't really remove the manufacturer indicator from these product names as they are not the traditional hyphenated or spaced names (e.g., Apo-benztropine, PMS Salbutamol)

In the CCDD, the manufacturer of the product is one of the "definitional attributes" that distinguishes one Manufactured Product from another, as it is in many medicinal product terminologies. When a manufacturer/supplier company purchases a product from another company in theory, there should be a new mp_code for the product in the terminology, just as there will be new GTINs etc. But the (buying) company can request Health Canada to keep the original DIN for the product, so the DIN stays the same but the description alters.
In order to make a sensible decision about how to handle this scenario in the CCDD, we need to be clear about the use cases and the context(s) of use of both the codes and the description that goes with the code, so answers to the following questions would be appreciated:
1) DINs are used extensively in prescribing and dispensing, both of which are 'point-in-time' events, so presumably a repeated prescription and/or repeated dispense could re-use a DIN, so a change in DIN/mp_code would require a new search for the product.
2) If a prescription is written requesting supply of “Exotowonder® 250 mg capsules [Fred’s Pharma Inc]”, is the pharmacist allowed to dispense “Exotowonder® 250 mg capsules [Joe’s Meds Inc]” without further ado (contact to prescriber etc.)? Is the manufacturer/supplier name considered to be part of the “medicine name” in the practice of healthcare?
3) If a DIN is stored in a record (e.g. in an EHR or DIS) what needs to be known from that DIN? Is who held the license for that product at that time important?
4) What is the value of manufacturer/supplier in a product name? Clearly it differentiates between products when there is no branding of any sort in the name (e.g. if only the INN is used), but does it also indicate to folk who they might contact for further information (e.g. to check on the likelihood of a rare adverse event or drug interaction)? Are there other uses?
There are clearly many other secondary uses that an identifier such as DIN can play a role in, including formulary management, but we'd be keen to have responses in the clinical areas above, please.
Many thanks