unpopular opinion: most of what gets said here about insulin syringe is guesswork
unpopular opinion: most of what gets said here about insulin syringe is guesswork — a position I have arrived at slowly and would like tested.
Aim the stream down the wall of the vial rather than into the cake. Reconstitution is a solubility problem, not a mixing problem, and mechanical shear does nothing helpful.
Reconstituted at 1mL when I meant to use a different volume. Caught it because the units looked wrong on the barrel. Now I write 30mg/mL on the glass before I put the cap back.
I keep a laminated card in the drawer with the arithmetic on it. Looks ridiculous. Has never once let me draw the wrong volume.
If two or three other people have done the same thing we might actually learn something. Alone it is an anecdote.
best — the order this archive was captured in
Wrote the date on the vial as well as the concentration after losing track of which one was opened first.
if the maths gives you a fraction of a unit, change the concentration
The lyophilised cake displaces a small volume, so the true concentration is very slightly lower than the arithmetic suggests. It is a fraction of a percent and it is dwarfed by fill tolerance.
the number you write down is the number you will trust at 6am
Research-use-only material is not approved for human use, so treat everything in this thread as arithmetic about solutions rather than instructions for a person.
units are a volume on a U-100 syringe, not a dose
That only works if the fill weight is exactly the label weight, and it usually is not exactly anything.
bacteriostatic water has the preservative, sterile water does not
15mg into 3mL is 5mg/mL, and 2mg of that is 40 units
That is sterile water, not bacteriostatic. Same appearance, different product, and it matters for a multi-draw vial.
That is sterile water, not bacteriostatic.
Right, and the arithmetic behind it: 15mg in 3mL is 5mg/mL, so 2mg is 40 units.
more water is not more drug, it is the same drug in a bigger volume
Agreed on the swirl. There is no reason to shake it and a good reason not to.
do the arithmetic before you reconstitute, not while holding a syringe
twice as much water halves the concentration and doubles the units for the same dose
twice as much water halves the concentration and doubles the units for the same dose
Adding one thing — put the date on the label too. Concentration plus date and you can never mix two vials up.
swirl, never shake
Yes. Writing 3.33mg/mL on the vial takes four seconds and removes the entire class of error this board exists to fix.
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