Insulin pen - is it OK to leave needle on?

I’m a long time syringe insulin user (37 years) but a newbie (9 months) pen user. So forgive me for asking such basic questions!

If I am traveling for the evening and want to bring my pen with me and don’t want to have to fumble for the screw on pen needle: is it OK to screw the needle on at home, take the outer “space capsule” off the needle, leave the little grey cover on the needle itself, and then put on the pen cap over the needle, and then (many hours later) use the pen for a shot, and then leave the used needle on the pen till I get back home (again many hours later)?

Last night for the first time in 9 months I noticed that this seems to be physically possible. That is, I just noticed that if I take the space capsule off the needle that the pen cap seems to fit over it.

This is kinda the modern equivalent of “pre-filled at home syringe” something I had done for ages with plastic syringes. But I don’t know if leaving the needle on a pen for extended periods is bad in terms of air bubbles getting into the pen or who knows what other bad effects.

Geez, we (wife and I) have left the same needle on for AGES. It’s the same thing as the opinion about changing lancets every time. Some can go months without a change (and suffer Zero ill effects) and others are paranoid to the point whereby they are compelled to change their lancet for every fingerstick. You can leaven the needle on for quite some time. You aren’t going to suffer from anything bad unless u jab the needle into something really nasty. And who does that?

Dave, does leaving the needle on, maybe require more priming (to remove air bubbles that might mess up dose), or eliminate the need for priming?

I’ve been mostly avoiding priming unless an obvious (non-tiny) bubble appears in the pen. I’m such a pen newbie that I’m not sure how the bubble got in there. I’m not sure if the bubble got in when I put the needle on, or took a needle off, or if it while happened some other time.

To be absolutely as accurate as possible, I’d prime it. Also, leave the pen in your body for a count of 10 to reduce the chance of leakage. leakage for people on small doses can throw off bg’s. 1/2U pens can help but not prevent those dosing errors.

I always left mine on for, I dunno, half a dozen injections or so, maybe even more when I was using 'em. I always put that teeny gray cylinder back over the needle each time, which could be kind of tricky in less than ideal circumstances. But yeah, I got over that “New needle for every shot” thing pretty quickly. Couldn’t make 'em last as long as a lancet (yes, you can change those–who knew?), but good for a day or three’s worth of injections anyway.

My daughter changes her needle tip about 3 times a day. It seems to get dull fairly fast if you use it much more. We always prime before every injection.

Definitely prime each time. Up to you how often to change it. Depends on how tough your skin is. If it starts to hurt, change it. What I do is toss the outer needle cap but keep the inner needle cap. That way I can put the large cap over the pen.

Although I have done this. I must say that you probably shouldn’t . If infections do occur, they can lead to bacterial endocarditis which is a risk and is serious. At times I get splitting in my fingernails, and this reminds me of this. So I would say no probably not don’t do it.

I have done this, but not a good thing. Needle gets dull. Air may get into needle. In my case the pen would drip and priming did not work and could not get accurate shots. Use generic pen needles. May fit good enough.