My buddys been doing oxy for a year now a never experienced any negative side effects until recently. He has a medium tolerance to opiates as well. He always takes 2 Roxi 30's (60mgs of IR oxy) or 2 Oxycontin OP 20's chewed. However, these past couple times he has done the 2 OP 20's, he's gotten cold sweats, nausea, and the shakes during the comedown.. Why is that? And why is it happening all of the sudden? He never gets it from the Roxies though