I have been Armour Thyroid 3 grain for several years and recently (December) started taking metformin 500mg /extended release three times per day. I had a Discectomy at L3/4/5 about fifteen years ago which was wonderfully successful. Every once in a while I will have some muscle/pain issues in my lower back when I do something stupid or do too much. Normally I take up to three 500mg Robaxin and Advil until I can get to the chiropractor and may continue for another day. Rarely do I take it for three days. And I never thought to ask the pharmacist about this when I picked up the metformin because I only need to take the Robaxin two or three times per year. Is it okay to take the Robaxin tonight so I can get some sleep? Would it be best to skip the Advil with it?