SWIM has been addicted to opioids for 6 months now he started smoking Roxy’s and for the past 3 months he moved to injecting Dilaudid (Hydromorphone). More recently SWIM has been doing 5-6 8mg dillies a day. He doesn’t do more than 1 pill at a time. He doesn’t get that much of a rush because he has been doing them too frequently. So anyway today, he really didn’t do anything out of the ordinary. He does his pill by coldshaking them(doesn’t filter them... just backloads them into syringe adds hot water shakes it up then shoots... he has been doing it this method a few months now when he gets the right pills) I’m telling you this because idk if it has anything to do with what happened. The most recent pill he did.. Everything seemed normal. He got his little bit of a rush that he enjoys and that slowy went away in like 20 seconds. Then he was high. And like 5 minutes after he did it he was sitting at his PC and his heart started racing and racing he instantly jumped up and started walking and pacing around in a panic. He said it felt like his heart was beating a million times a minute. he was so close to calling 911 because he had no idea what was going on. This has never happened to him before. He didn’t hit any weird vein or he didn’t use any cotton so it couldn’t have been cotton fever. This went on for like 5 minutes and it slowly started to get better. It scared the shit out of him. It couldn’t have been an overdose right? Overdoes don't have any symptoms like this that I have read about? Unless there's a like different type of overdose? Anyone have any explanation?