rofl the only "safe" way to do any stimulant is orally, but usually tastes like shit, and if ur looking to get "up" re add the coke in coca cola, also works for addiction as well. anyway, dxm is a psychedelic dissociative that has stimulant properties, so 2 potent stimulants mixed together really is a no brainer and was bound to have negative effects on your heart dude... i even had a bad experience with caffeine and methylphenidate which were even low in dosage but still caused discomfort.