Solostar vs Pen and Cartridge

I started on Lantus mid-December and have been using the Solostar pens. I have been titrating my dose and currently take 36 U every night. I suspect that the Solostar pens may not be entirely consistent in terms of dose delivery and was wondering about going to another type of pen and lantus cartridge. I have weeks on one pen when my BG in the morning is low to mid 6's and then with a different pen, same dose, my morning BG's are mid 7's. My diet is consistent and i carefully refrigerate the pens etc. Just wondering if anyone would recommend the pens and cartridges over the Solostar in terms of dosing accuracy and consistency ?


I asked the same question on here several years ago, although regarding ultra small doses in pens vs syringes. Someone provided a summary to a legit study which showed, to my surprise, that the pens were actually more accurate than syringes

When I used pens, both disposable and cartridge based, I noticed that insulin will continue to seep out for maybe 7ish seconds, so you really do need to keep the needle in the skin for the recommended 10 seconds to get the full dose. I'm assuming, anyway, that that's the full dose, and not an overdose somehow.

I assume you're also priming out air bubbles if/when air gets sucked into the pen due to atmospheric pressure changes, insulin leakage, etc.?

Yes priming each time, I don't find that I really need to use 2 U but 1 U seems to work fine - except perhaps the first use of the pen.

I count slowly to 15 after the plunger is fully depressed to make sure I give it a good ten+ seconds.

I was just wondering whether the pens plus cartridges are any more accurate than the disposable Solostar. My theory being that perhaps the consistent use of one pen over time delivers a more repeatable consistent dose, as well as being more eco-friendly I suppose.

Interesting stuff. Hard to imagine a pen being more accurate than a syringe but it is all a learning thing for me after years on oral meds. I don't mind the needle at all and I can do it just as fast as taking a pill. However I do wonder between pens what the manufacturing tolerance is, and whether 36 U from one pen is actually 36 U from another one. This is only based on the casual observation that one week with one pen I am one consistent morning BG average. But the next week with another pen I seem to get a different BG average.

Here's a link to a 1998 study showing pens are more accurate for small doses. I would imagine they might be even better now since pen designs have improved over the years.

Yep, I had the same experience priming.

The design of the internal parts should drive the dose, absent malfunctions, and the tolerances must be pretty tight to get FDA approval. So absent a malfunction, which I suspect would be obvious, I suspect they're pretty consistent both within and across pens. It's plausible that a more robustly built reusable pen could be a little more precise, but conversely over time there's also room for its performance to change a bit.

I always used disposable pens for Lantus and cartridges for Humalog/Novolog, made them easier to keep apart.

thanks, interesting article and conclusions