Discussion Forum

I agree with this proposal. Consolidating these two overlapping hierarchies is a good idea - and the << |Unit of presentation| concepts are the ones that need to be kept, due to their significant usage in the drug model. With respect to concepts in the |Unit dose| subhierarchy that are not semantic duplicates (e.g. scoop, spray, squirt), moving these into the |Unit of presentation| hierarchy would require SNOMED's definition of "Unit of presentation" to become broader than that used by EDQM. However, it would certainly be much simpler, from an implementation perspective to have these all together in the same subhierarchy.

The content team has developed some examples for PCDs, starting from on the editorial guidelines for the CDs in the international edition, these are shared here for your consideration: Clinical Drug (CD) with a single ingredient: FSN: Product containing precisely amlodipine (as amlodipine besilate) 5 milligram /1 each conventional release oral tablet (clinical drug) Synonym: Amlodipine (as amlodipine besilate) 5 mg oral tablet Clinical drug (CD) with multiple ingredients: FSN: Product containing precisely amlodipine (as amlodipine besilate) 5 milligram and valsartan 80 milligram/1 each conventional release oral tablet (clinical drug) Synonym: Amlodipine (as amlodipine besilate) 5 mg and valsartan 80 mg oral tablet PCD Template: Package containing <pack size> of <clinical drug (CD)> (packaged clinical drug) PCD with single ingredient: FSN: Package containing 28 tablets of amlodipine (as amlodipine besilate) 5 milligram/1 each conventional release oral tablet (packaged clinical drug) Synonym: Amlodipine (as amlodipine besilate) 5 mg oral tablet 28 tablet pack Synonym: Amlodipine (as amlodipine besilate) 5 mg oral tablet 28 tablet  PCD with multiple ingredients: FSN Package containing 28 tablets of amlodipine (as amlodipine besilate) 5mg and valsartan 80mg/1 each conventional release oral tablet (packaged clinical drug) Synonym: Amlodipine (as amlodipine besilate) 5mg and valsartan 80mg oral tablet 28 tablet pack Synonym: Amlodipine (as amlodipine besilate) 5mg and valsartan 80mg oral tablet 28 tablet Please let us know if you have any feedback or preferences. The plan is to enhance the documentation to include examples of naming conventions for extension classes. Best regards Alejandro

fhielkema  If we cannot come to a resolution and consensus from the DEUSG prior to October, I think this is a good topic for discussion by the EAG.

Again, as I said earlier "the problem is (not really) about "hydration" ... but that the INT model/content is too precise." "Hydrates" ARE imporant when it comes to strengths (BoSS relationship). Are they clinically significant? Different therapeutic effect etc. Different countries may want to be more/less precise based on their own requirements (often legislation/registration requirements). Being too precise in CORE is what's causing the problem. The only way to fix this problem is to accept there's an issue with the model/modelling. Julie's slides illustrate this. Amoxicillin "Poster child" - 323509004|Product containing precisely amoxicillin 250 milligram/1 each conventional release oral capsule (clinical drug)| There is no such thing as a product that contains "precisely Amoxicillin". This concept was created as a replacement in 2021 as a replacement for 783279000|Product containing precisely amoxicillin (as amoxicillin trihydrate) 250 milligram/1 each conventional release oral capsule (clinical drug)| Saying "precise ingredient" means that's precisely the ingredient... it's obviously not as some extensions want to be more precise and say trihydrate. The intent of "precise" was to stop subsumption. Back engineering exceptions to handle hydrates, avoids the problem. Alendronic acid - 783144007|Product containing precisely alendronic acid (as alendronate sodium) 10 milligram/1 each conventional release oral tablet (clinical drug)| Again, this product was created as a replacement for 325974004|Product containing precisely alendronic acid 10 milligram/1 each conventional release oral tablet (clinical drug)| Why does the INT CD need to be so "precise"? In AMT we simply say 45274011000036109|Alendronate 10 mg tablet (clinical drug)| RCDs could be more precise. (Though we don't get more specific in AU) But UK do. They have 39728011000001102|Alendronic acid 10mg tablets (product)| with a subtype 5546111000001105|Fosamax 10mg tablets (Dowelhurst Ltd)|, modelled with a "specific active ingredient=Alendronate sodium" The international CD being too "precise" is causing the problem. Tiotropium -This is a really good/interesting example. I'm not sure, but I suspect it's the different inhaler devices (rather than the formulation) that affects the strength vs delivery. The difference between strength/dose/delivery values has been something AMT has had to grapple with - at the moment we just model strength - 18ug or 13ug - and not what's delivered. Thus there's nothing in the terminology indicating both products are "10 ug". Side note: The BRALTUS example in the slides says 16ug/acutation. At least in AU it appears to be 13ug Here's a snippet from the BRALTUS insert in Australia Braltus capsules contains 13 micrograms of tiotropium (equivalent to tiotropium bromide 15.6 micrograms) as the active ingredient. During inhalation, 10 micrograms of tiotropium is delivered from each capsule from the mouthpiece of the Zonda inhaler. Braltus and Spiriva both deliver 10 micrograms of tiotropium and are equivalent. SPIRIVA Spiriva contains 18 micrograms of tiotropium (equivalent to tiotropium bromidemonohydrate 22.5 micrograms) as the active ingredient. AMT doesn't mention the specific salts at all. This is an exceptional strength modelling scenario. But not really about "hydrate subtypes". SOLVATION - deemed clinically irrelevant so excluded. But if extensions wanted it, they could. No problem. So long as the INT content isn't too precise. Amlodipine  - This diagram implies that a "grouper" is something different. It's not. Any concept that subsumes something else is "grouping". Having "Precise CDs" is what's causing the problem.  AU has 23517011000036108|Amlodipine 5 mg tablet (clinical drug)| UK has 39732011000001102|Amlodipine 5mg tablets (product)| Ireland has 267451000220105|Product containing only amlodipine 5 milligram/1 each conventional release oral tablet (clinical drug)| (This subsumes the 3 specific salts just as the example in the slide) US (RxNorm) has 197361|amLODIPine 5 MG Oral Tablet| What does “Amlodipine (substance)" mean? - It means Amlodipine... Or to be really pedantic Amlodipine unmodified. What would "Amlodipine 5 mg tablet" mean - It means "a tablet containing (only) 5 mg of amlodipine" - see the Irish FSN. I can't speak for the other countries, but in Australia a prescriber would just choose "Amlodipine 5 mg tablet" (the clinical drug). And the pharmacist could dispense any of the specific salts (RCD). Ireland have just modelled their CD with |Has active ingredient| rather than |Has precise active ingredient| to get the expected subsumption. Again, the Clinical Drugs are inherently abstractions. The are not Real (clinical drugs). Thus saying "precise" is generally unnecessary (there might be some exception). Amitriptyline - "Amitriptyline 25 mg tablet" doesn't exist in SCT, because it doesn't exist - Amitriptyline always comes as Amitriptyline hydrochloride. IF there was an Amitriptyline (not HCL) 25 mg tablet, there wouldn't be a "CD Grouper" because they have different strengths. Though they would both be subsumed by 778301005|Amitriptyline only product in oral dose form| Now, I see the UK has 42291211000001105|Amitriptyline 25mg tablets| - but it is modelled with "Has specific active ingredient=Amitriptyline hydrochloride" I'd say this is because Amitriptyline always+only comes as hydrochloride - so it's easier to just say/write "Amitriptyline" and there's no clinical ambiguity. Perhaps their FSN is inaccurate. But the PT reflects clinical use. And I'm certainly not saying there's anything unusual about the UK approach. See this Australian website - Amitriptyline 25mg Tablets https://www.medshop.com.au/products/amitriptyline-viatris-tab-25mg-50amitriptyline-hcl-25mg-tab Our "RCD" for this product is 742031000168109|Amitriptyline (Alphapharm) 25 mg tablet| - subsumed by 22788011000036102|Amitriptyline hydrochloride 25 mg tablet| The modification is important (because it's against the BoSS). But we don't HAVE to say "Has precise active ingredient=Amitriptyline hydrochloride" "Has active ingredient=Amitriptyline hydrochloride" or even "Has active ingredient=Amitriptyline" could be just as applicable for an abstract concept like CD. With the added level of "what people expect". Irbesartan - I had no luck finding a "Irbesartan hydrochloride product". So ... But the question - "How could a user distinguish that the Irbesartan CD here is a different type of concept from the Amlodipine grouper concept?" This is an implementation consideration - and refsets are the easiest answer. e.g. "a prescribing refset". We don't allow users to select any "CD" within Australia - only the ones relevant to Australia. This is something that would apply to EVERY country. This is about implementation support. Perindopril (not in the slides) but another example like Tiotropium. "Perindopril erbumine 4 mg tablet" and "Perindopril arginine 5 mg tablet" - both contain the same amount of "Perindopril". This isn't obvious from the model (any model AFAIK). But again, comes down to what use cases are supported and implementation advice. (Multiple options, but beyond this topic). So in summary. This problem is NOT an issue with hydrations. It's a problem with the INT model/content being more specific than some extensions want. The solution is to drop "has precise ingredient" from CDs in core/INT and just use "Has active ingredient" or something like "Has specific active ingredient" (that sits between HasAI and HasPI, with an appropriate property chain). (Thanks to dmcmurtrie & mkeary for helping me with the details on this)

Completely agree with Linda (and have communicated such, the past 2 years). For EDQM mapping - What are the specific requirements for that? Who is using the map? Do the attributes all need to map also? Or is mapping the Forms sufficient? I've copied my previously submitted SNOMED CT/Implemenation Use Cases below. When we try and give implementation guidance to users of the terminology. Imagine a UI for creating dose instructions or prescriptions. The clinician selects “Paracetamol” (90332006) Then clinician selects the “route of administration” Which set of values should be used here? Intended site – Oral (738956005), Rectal (738986003)               Or               Route of administration - Oral route (26643006) , Rectal route (37161004) A route of administration value set already exists Valueset-route-codes - FHIR v5.0.0 (hl7.org) https://www.hl7.org/fhir/valueset-route-codes.html, and is referenced for Medicines, allergies and procedures (re-used). However, these codes have no relationship for the medicines terminology. If we used the range (whatever that might be) for “Dose form intended site”, we can actually leverage the terminology within our implementation! e.g. a backend “ECL template” <@MedicinalProduct@: |Has manufactured dose form|=(<|dose form|:| Has dose form intended site|=<<@Route@) User enters “Paracetamol” + “Oral” -  (<90332006:411116001=(<736542009:736474004=<<738956005)) Code Display 322325004 Acetaminophen 1 g and codeine phosphate 60 mg effervescent powder for oral suspension sachet 1172863005 Acetaminophen 1 g oral tablet 1230156008 Acetaminophen 1 g powder for oral solution sachet 1172864004 Acetaminophen 1 g prolonged-release oral tablet User enters “Paracetamol” + “Rectal” -  (<90332006:411116001=(<736542009:736474004=<<738986003)) Code Display 1201762004 Acetaminophen 100 mg rectal suppository 322256005 Acetaminophen 120 mg rectal suppository 322278003 Acetaminophen 125 mg rectal suppository 322254008 Acetaminophen 240 mg rectal suppository 322257001 Acetaminophen 250 mg rectal suppository It might be possible to get away with using a "mapping between intended sites and routes" - but this is just another barrier to implementation. Either somehow incorporating the mapping into ECL or client side processing... This stuff is hard enough already without adding hoops to jump through. For clinical implementations there's many gaps in SNOMED CT for forms - particularly for abstractions that are useful clinically. For example we have groupers like 778317004|Amoxicillin only product in oral dose form| and 385268001|Oral dose form| But we don't have an single concept like |Amoxicillin only product in oral liquid| or |tablet/capsule dose form| - which are useful in prescriptions where the prescriber doesn't care if it's a tablet or capsule, or if they patient has trouble swallowing.

I'll let dmcmurtrie comment on Hybrid Reasoning approach further. But our meds tooling can effectively do this also. Users author by essentially filling out a form and the tool uses this information to author up to 6 concepts at once. The tool can be configured to let the user enter strengths in whatever strength they want (e.g. 1.5g) but creates a strength as 1500mg - or whatever the target unit is. The conversion is trivial* (there are no molar <> mass conversions). We just don't store the input strength, but that could be added. And the NNF would be as you said.  Which is feasible, but I'm wary the "complexity" will breed poor implementations. * The one non-trivial conversion is for a strength like "200mg/3mL" (What that 3mL actually means is also a challenge for the model... ) "validation between stated attributes and descriptions" - this might work for other content. But severely underestimates the complexity of requirements and editorial rules for medicines descriptions. The reason for most of our approaches to medicines authoring and modelling is that we needed a solution 10+ years ago...

I agree with Dion that creating some more general CD-level concepts (using |Has active ingredient| instead of |Has precise active ingredient|) with just the base (unless everyone agrees that the salt form is clinically significant or always the BoSS) and potentially a more general dose form (could this even use a |Has dose form| attribute, rather than a |Has manufactured dose form| attribute?) is a good way forward. Also agree that these should subsume the more specific CDs. it would be great if this approach allows the existing CDs to use the hydrated form of their ingredient as their precise active ingredient, to solve the hydration subsumption issue. For example:    New general CD - |Amoxicillin 500 mg oral capsule| : |Has active ingredient| = |Amoxicillin|, |Has dose form| = |Oral capsule|)    Specific CD - |Amoxicillin (as amoxicillin trihydrate) 500 mg oral capsule| : |Has precise active ingredient| = |Amoxicillin trihydrate|, |Has manufactured dose form| = |Oral capsule|

Thanks for the summary ygao! With respect to the |Has container type| attribute: The CMT is using a domain of << 781405001 |Medicinal product package| for this ... so as long as these are included in the international domain, we're covered The CMT is using a range of << 398124009 |Drug container (physical object)| ... so as long as these are included in the international range, we're good The CMT does not group this attribute, so we're okay with this approach. The CMT uses a cardinality of [0..1] on MPPs in general - but we have exactly one ([1..1]) container on each of our "Containered clinical drug" concepts (which sits below "Packaged clinical drug" in the model). Note: Allowing a container to be added on a multi-container product enables the ability to define both the outer container type (on the multi-container MPP) and the inner container types (on the contained MPPs), if required. 

ningram - we agree with using the same approach for the vaginal ring concepts. We've got at least one actual product (Estring 7.5 mg/24h) that corresponds to this pattern. Seems like a good idea to produce "Vaginal delivery system (unit of presentation)", looking at the relevant dose forms in EDQM.