I don't think you should drug yourself before jump, you don't want to fuck something up. I think this thought has anyone when they think about doing it. Its like pulling the trigger, when you think about it, you anxious but in the moment when you are ready to die and set up a time and date you just will pull it. Maybe you haven't this courage because this is not your fav method. Use a method what you like, its 1000 times easier. Some ppl like hanging, jumping, I could never jump or hang but I could lay my neck on some tracks. Every person is diffrent.
But when you like to jump, believe me in this moment when the adrenalin Is kicking, and you should tell yourself what you want. If you wanna jump, just jump. When not, then don't jump. Its just a brain thing.