Is the xanax/vicodin cocktail really necessary before tumescent lipo?

i am extremely sensitive tomedication. I will have lipo on my front and back bra rolls, hips and outer thighs. i was told be4 the surgery i will be given the cocktail but amworried of the effects and i dont want to take anything. i've had vein stripping w/o sedation succesfully. i ask is coz the doctor is strongly suggesting the cocktail and i want to make sure it is not a dangerous mix and that any of the drugs arent necessary to help the effects of the anesthesia and i can decline to take it.