Lortav, Norco, and Vicodin are all combinations of hydrocodone and acetaminophen. Just different amounts.
I know, it turned out to be the yellow dye in the NORCO. I called Vintage, and they said changing the shape which made it easier to swallow and the dye with lowering the Tylenol was the only changes they made. I react to some red dyes too, those are usually food ones.
Dr solved the issue and wrote for 5 mg to take once daily as 10 mg, no issue except the short time span it works.
Since most of the pain is OA, I am going to have to see if they have any new OA drugs that work longer but do not tear up the gut. They gave up on me a decade ago with those.