Hi. Not that you need anymore information about Butalbital, but I used it a lot for menstrual migraines for years. Yes, it's the caffeine that will interfere with your sleep. The caffeine is good for the headache because it expedites it into your bloodstream and also provides vaso-constriction to lessen the pain.
The barbiturate (sp) effect works great for relaxing spasms in your head (that's my personal experience). Extra information: I've taken two tabs when I had serious headache and have repeated dose at 3 hours. I wouldn't push it beyond that though. My neurologist actually suggested that. You can also take Tylenol with Fiornal (nor Fiorcet!!) because they are different medications. Of course nobody would ever, ever suggest alchohol with this type of med but I allowed myself one drink while on it and even though I felt a little more drowsy I was not in danger-just in case you are out for dinner or something. I think it can be an addictive drug so be judicious when using it. But as I said I got relief from it like no other med so don't deny yourself the right to feel pain free.