I'm sure others have encountered this one before also. But for some reason I have 3 Drain Vitality shouts in my shout list... The first one; Stamina-Magicka-Health is the right one, the other two are marked as Kill-Leech-Suffer, the same words used for the Marked for Death shout (they seemed to be linked to that one, and not Drain Vitality despite having it's name) Reason I say that is because after learning the 3rd word for Marked for Death I got a second glitched Drain Vitality in my shouts list! I doubt there is any way I can make them go away other than Bethesda fixing in the next patch...?