I take the Norco also; 7.5/325. I asked my NS the other day if, in fact, it works differently than Vicodin. He said yes, but did not go into great detail. It just seems that Vicodin works much better for me. I can take just ONE a day and I am good to go. With the Norco, I have to take 2-3 a day; normally just two. In any case, neither one of those upset my stomach. But Percocet will! I get nauseated and bad headaches with it. So, yes, maybe someone will come along and explain why.