I had some issues as well when I started Humalog. Sometimes it worked wonderfully and predictably, other times I may as well have been injecting water.
One day a 20g carb meal with 4 units to cover (I was 110ish before the meal) pushed me to 260 despite a 30 minute pre bolus. When I added a correction I noticed the dosage window didn’t “wind down” as it normally did, there was a fair bit of pressure required to push the plunger and it skipped and did a quick jump to zero. I did a bunch of air shots and roughly half the time that pen would not deliver ANY insulin.
After that episode I grabbed a new pen, and any time I gave myself Humalog I made sure to take my time and look closely at the dosage window while administering the shot. I began to notice a trend that as my pens got older (1.5-2 weeks) they began to require more pressure to get the dose out and would begin to “skip doses”. A call to the manufacturer suggested it was the needles I was using (Bd micro), though the same needles work perfectly with my Tresiba.
I didn’t have any problems with other pens I’ve used. I really preferred the click, click, click feel of my Novalog pens and Tresiba pens. Its my personal opinion that the Humalog pens are cheap junk. Unfortunately Humalog is the only rapid insulin my insurance covers…
At my last endo visit I requested the non disposable Humolog luxura hd pen that uses vials of insulin. So far I’m really happy with it. its been 2.5 months so far and it hasn’t skipped a beat. With the disposable quick pen when I’d prime it sometimes it would just dribble, others it would produce a steady stream (I always purged all the air and most days spent more insulin priming than I used for my dose). The Luxura always produces the same size stream for a 2u prime once air bubbles are purged.
So far I’m really happy with the non disposable pen and vials. The only downside is the pen is HUGE compared to the disposables, Though its worth it to me as the anxiety of wondering weather or not I received my dose was really uncomfortable. As a side note I use the same pen needles (some from the same box) on the Humalog luxura and have not had a single stiff plunger, which was becoming a common occurrence after a week and a half or so with the quick pen.