choose a name

i don't know what is this drug, how do they come up with these names when you see the name called Leptorexin, what looks in your head.

For real right now i am watching the tv and they are talking about Sam-e which helpls with bad moods and Motrin which helps for headaches and then there is Prozac and then you have Vioxx and Viagra and the list goes on how do they come up with these names oooooooooooooooooooooooo