Technique for using an opened penfill in an insulin pen?

I wonder if anyone has evolved a solid technique for installing and reliably using an already partially used penfill into an insulin pen?

The only way we have found so far is to install the penfill as usual, then keep on “administering” insulin boluses in the air (typically 10 units to start with) until we see insulin spurting. Then we lower the number of units to 2, and keep on doing it until 3 consecutive 2-unit injections produce a solid insulin jet.

Are you talking about somehow using a disposable pen, or using a reusable pen?

When I was on MDI using just reusable pens, I had long- and rapid-acting in two separate pens, so there wasn’t usually a need to put a half-used cartridge into a pen (since when a pen was empty, I’d just replace it with a full cartridge).

But, on the odd occasion I put a half-used cartridge in a pen, I’d dial up 20-60 units (depending on how emptied the cartridge was and how many units the pen could dial up) and do big boluses like that until the plunger began approaching the cartridge stopper, then I’d switch to smaller increments like maybe five units, and once I got a squirt of insulin, I’d do a final one-unit test and that would be that.

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We just pull out what we need with a syringe. Remember not to push extra air in, it isn’t needed.

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I meant a reusable pen, sorry. Sometimes it is convenient to insert a partially used cartridge. Thanks a lot for your MO!

As long as there is no air in the cartridge, once you have insulin coming out you know the pen screw is pushing the cartridge plunger. Maybe I am not understanding your question. Just dial up and press the dose button until you see insulin coming out.