Refilling the Lilly KwikPen disposable pen

The Lilly KwikPen is a disposable insulin pen. But a lot of people may not know, you can actually refill it and re-use it!

It’s very easy to do. Just two simple steps

Notice in this picture how the plunger is all the way to the top. This Kwikpen is empty. Also notice that the black advance screw is pressed up against the plunger.

This is the dosing button I am referring to:

Step 1:
Hold the base of the pen. Push the dosing button up into the base of the pen, and while holding it up into the pen, turn the dosing button counterclockwise. This is the opposite direction you do when dialing up your dose. Keep pushing the button into the base of the pen and turning the dosing button counterclockwise. As you turn the dosing button, you will hear click sounds, and you will see the black advance screw moving away from the plunger.

Now, notice in this picture how the black advance screw is no longer pressed up against the plunger. Now you have space to put insulin back in the reservoir.

Step 2:
Simply add your insulin. Just take an insulin syringe filled with insulin from a vial, and refill the reservoir. Now you can reuse the pen! If you see an air bubble in the reservoir, just use your syringe to withdraw the bubble.

Since this is just a simple demo, we don’t want to get into mixing different insulins or diluting. I will save that for another day.

Why do this?
Vial insulin is cheaper than pens. And I have found that these disposable pens are one of the more expensive items!

But if you do the refill and reuse process just 3 times after the pen’s initial use, you have made it 1/4 of the price. :wink:


This is awesome! I could use this trick to refill pens with R and NPH too! I assume it doesn’t work with novolog pens?


I have never used a novolog pen, so I am not sure how those work.

This is a stunner! We’ve finally found something that @eric hasn’t tried! Great demo! Thanks for this.


Yeah, endos all across my state and my insurance company are starting to get a little suspicious… :sushing_face:


They probably also wonder why you keep buying insulin in 100mL buckets…now they know.


I have a bunch of Novolog pens, I’ll work on a procedure in the next few weeks, unless someone preempts me:slight_smile:


@michel the conversation we’ve been having would make more sense if transferred to this thread

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So— how can we COMPLETELY drain a humalog pen in order to refill it with Regular? Does it matter is there is a few units of humalog left in the tip? Should it be flushed repeatedly with a sterile dilutent?

I think a an R pen would really fit the bill for me a lot of times… maybe a splash of R and a snort of afrezza-- it’d open up whole new realms of possibilities


If it was me:
(a) I would flush it completely, because N being a mixture it itself may not be miscible with anything else, and
(b) I would flush it with the new insulin we are putting into the pen.

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The thing is to truly completely flush it, to the point that there’d be no potential chemical reaction— were talking about so many flushes it’s absurd… theoretically infinite-- so I’d really like to know if it actually matters or not from a chemistry perspective


I am not sure!

I was considering doing just that myself as well (not with N though). I had decided that, if I did, I would fill the pen cartridge once, empty it, then from there on use the new insulin in the pen.

But I have no proof that this is correct. I figure it is, from the following calculation:

  • on a 3 ml cartridge, I am guessing, by eye, we may have at most 6 U left (2%) when we are done pushing the plunger

  • If I fill it once, then shake it well and empty it again, the new mixture was 98% new insulin and 2% new insulin. If I have 2% left before I fill it for real, I would have roughly 0.1U left of the original insulin. Even if it all went in one dose, that would not be a big deal I figure.

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It certainly wouldn’t be a big deal in terms of the action profile of the trace insulin having a discernible affect on the user-- unless it caused a major reaction with the other… I’d have to assume we’d have heard about it if it was really a thing… I’m sure there are plenty of insulin users out there using the same syringe from one vial to the next…


I guess another option would be to fill it with water and empty it several times, then let it dry. Or use dilutant and do the same thing. Either would be cheaper I suppose – although not as safe as using final insulin as the throwaway intermediate.

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But there’s no way to fill it with water and let it dry-- if you put it there, the few units that aren’t ejectable are staying in there like it or not

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You could leave a syringe through the membrane with no plunger.

But that may not be sufficient to let the water or solvent evaporate. I am not sure :slight_smile:

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Crap this isn’t even the thread I meant to be commenting on I thought this was the one where he showed how to refill a kwikpen not a cartridge— damn 2" iPhone screen

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Ask and you shall receive :slight_smile:

As long as you don’t mention Obamacare.

I can’t afford to mention Obamacare.

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You can refill either a cartridge from the non-disposable Lilly pen, or a disposable Kwikpen which has a built in cartridge. Either one. Here is the other thread:

If you fill it with 300 units and flush it as fully as you can each time, after the 3rd flush, this is the purity of the insulin you have in it:

Each time you refill it, it moves more toward completely pure. Of course it never gets to 100%, but when you have something like this, 0.9999997905950370000, I think you are in good shape.

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