If you are getting actaul proper coke then 50mg is a massive shot. I have done shots as small as 20mg and thought i was having a heart attack, not nice at all. My man says most people cant be trusted with proper drugs as they would all be going over left right and centre. Proper coke 70%+ is a dangerous drug as people are to used to cut to fuck weak shit. A friend had a heart attack from sniffing decent charlie and had only done about half a G and she was a long term user. I would not fuck with iv coke as you are either going to get a mega habbit and if you are shooting normal coke then i dread to think of all the cuts used, pure coke is bad enough for your veins -I caused major damage to an area in my arm and its always cold and has no sensation so i think i stopped before it got alot worse.