Agreed! As both a former medic and as a cancer patient, I too appreciate that kind of OCD in my own care, and believe me, that level of care was needed when I had no neutrophils from leukemia!
Blackhawk, ajax31, and Abonicex
I do not want to suggest someone increase their dose, or extend the pin times for a day or two without due diligence.
I would rather people pin ED, EOD, or Q3.5 days depending on their comfort level, and if IM or subQ.
I was expressing my thoughts of managing my needs in a similar situation, based on MY risk tolerance. I have spent my entire career(s) in two fields that share the same risk / reward ratio of overkill engineering, Nth degree goals, extreme measures, cost be damned, "what would you do if your daughter's life depended on your performance" type choices. I should have been more clear, and thus the reason I rarely interact in these situations.
I have seen abscesses from injections gone bad. Some serious ones. Some life threatening ones. Some that changed the person's life due to the necrosis of the tissues, lost 80% of their glute, or 60% of the quad, kidney failure etc. Either bad product, bad technique, bad luck, or bad follow thru.
What "I" would do, given my risk tolerance, and ranking of quest for cleanliness, infection avoidance, is to split the dose into the desired mg amount, (this case 100mg per occurrence, and waste the incremental amount left over. (Dollar verses disease ratio.)
If the ampule was dosed at 250mg/ml, and I needed 100mg/dose, I would split the dose amongst two syringes, and 'waste' the left over. Reluctantly 'store' the second dose in the fridge in a glass meal prep container.
I would consider the left over 50mg not worth the risk to add to another ampule's left over 50mg to 'make' a 100mg dose.
With respect to 'popping the cap' of a SINGLE USE ampule and 'making' two or three syringes of product, and the potential risk of 'storing' a dispensed product 3 weeks...
I wouldn't do it. here is why.
A multidose syringe 'supposedly' has a different preservative level, and different solvent level than a single dose ampule. Thats what we are taught. A single dose container, specifically a glass ampule with a 'breakable neck' has zero barrier to picking up contamination from the air once opened. That is why you 'use' it immediately.
The small vials (1 ml) in the US do have the rubber seal, and the breakaway tin cap. You can use these for multidose, or the 10 ml vials with the same features.
In the most respected facilities the 'throw away" date is either 14 days, or 28 days from "popping the cap" on a multidose vial.
And while I am not a pharmacist, just a 'nurse', but based on experience, luck, curiosity, blessings, reading, experiments, and a touch of watching and working.
So I can not give a opinion with 100% accuracy about the accuracy of our teaching lessons(s), I could not recommend (I would strongly discourage.) utilizing the single use ampule and storing the product outside the ampule for 3 weeks,
YMMV, and I apologize if I am making this uber convoluted.