like post #3 from Doug, I too am able to use them with an Ortlieb handlebar bag. Angling the levers downwards slightly is the natural position that I have all my brake levers positioned anyway on my flat bar bikes , it's simply a more natural position for my fingers to rest on and get to the levers ---so the added bonus here is that you generally should have room to have them on dropbars while using a barbag (not a roll bag obviously).

the great thing here is that its easy to try out, simply angle them down and see.
I won't look for my photos, as the setup looks just like Dougs, but while its a tiny bit tight, I can and do use my interrupter levers when riding with my hbag on.

hope it works out for you. Perhaps if you have giant stonemason hands it might be trickier, but only way to know is to try.