Re: [Gnumed-devel] Medication schema - how to represent concentration

[Jim Busser]

On 2011-09-05, at 5:26 AM, Karsten Hilbert wrote:

> No, not really. The ref.consumable_substance table holds
> substance names along with their typical/ available/
> recommended dosages. Perhaps a better name might be
> ref.pre_dosed_consumables or something to that effect.

When populated from lists of commercially available substances, this table (as 
currently defined) easily accepts

        the strength in which the drug is supplied/available

which will commonly form what could be thought of as a "base unit of dosing".

'Typical' dosages will most often be half, the same as, or double (or perhaps 
triple) this so-called 'base' of what is possible.

'Possible' dosages are infinite, and are probably best not pre-defined… it 
would be better to just let them be created / recorded in patients' actual 
records.

If ref.consumable_substance were to be used to store 'typical' dosages, it 
would not be enough to just store

        description
        amount
        unit

… the various schedules (1 0 0 0, 0 1 0 0, 0 0 1 0, 0 0 0 1, 2 0 0 0, 0 2 0 0, 
0 0 2 0, 0 0 0 2) would need to be stored and at that point, if the row 
contained

        ramipril 20mg 0 0 0 2

but the capsule is only available in strengths up to 10mg, where the 20mg is 
achieved by taking (2 x 10mg) it becomes a worry what the 0 0 0 2 means because 
without the knowledge (content) of the 10mg strength it risks to look like we 
are talking a bedtime amount of 2 x 20mg.

I suspect you may be thinking to achieve some equivalent to the DDD but it is 
IMO important to not 'lose' the distinct information as to what is available to 
be taken and I think it remains important to preserve the base strength (of the 
available tablet or capsule) that the patient is supposed to use or turns out 
to be using, because patients think in terms of "how many am I supposed to 
take" and not doing 'the milligram math'.

That is why I have the feeling that

        ref.consumable_substance

(at least for commercial substances) should remain the strengths in which they 
are available. 

For the purposes of re-selecting dosages that have been previously-prescribed 
in the praxis, maybe the phrasewheel in Schedule can be constrained to values in

        clin.substance_intake.schedule referencing the fk_substance (or 
fk_drug_component)

that was in focus in the top portion of the 'Adding medication /non-medication 
substance intake' widget. Does it already do that, or does it offer all 
schedules regardless of which substance(s)?

-- Jim