I have looked at the videos and searched here, but the injector I have does not have a seal that can be broken. The top part, up toward where the injector button is, does not twist apart or pull apart, as has been described -- it's all one piece.  It's from Sun Pharma.  I'm sorry if I'm repeating, but I have searched before asking this. I see some people talking about hacksawing it open or using a bread knife -- Is that for this model?
THANK YOU!!

I have no experience with injector pens but have seen your question before. It was suggested to get some needles like those for diabetes (I don't know the proper name for them) Squirt the sumatriptan from the injector into the needle then use the partial amount you need. I'm sure someone will be along soon that can explain this better.

Hi CHfather

I heard somewhere that sun pharma had stoped making the auto injections, and when current stocks are gone there will be no more.

Anyway, if you google "cluster headache splitting injections" you'll find a you tube thing of a guy wearing a cap showing you what to do.  I THINK they are the sun pharma ones.

Alternatively, if you can get some syringes with needles on - the kind diabetics use, you can trigger the auto injection into the syringe, and then use half at a time.

Hope this helps
Maz

Thank you, Bob and Maz!  I've got it.  The video did help (and there are a couple more out there now, too).  Somehow, breaking apart that tube was a lot harder for me than it seems to be on any of those videos. Technique, I guess.
Again -- thank you.