Wow, you were taking 400mg a day, thats 40 10/325 Norcos, No way the 2 5/500's will do much. I have spine pain as well but will not go over 5 Norcos a day. Atleast thats what ive been doing for a year now, from 2 to 5 a day, depending how my pain is. I find walking 2 miles a day actually helps reduce pain.