I usually take 15mgs of percocet,oxycodone. But i ran out today. I have a ms contin(morphine sulfate) 200 mg pill. How many mgs of morphone will equal to 15 mg oxycodone? Can i defeat the time release by chewing it? I guess do the math of opiod tolerance with no cross tolerance to morphine. Im hurting bad, so plz dont judge just answer, and how long does it last in ur systgem?