Pain
"Have had Dilaudid squirted in my IV at the hospital.  Works immediately within seconds and can rid you of all kinds of awful pain.  It will allow a peaceful sleep, and you will be staying in a laying down position anyway because it makes you feel so loopy.  After about two hours it wears off a lot but you still feel better than you did.  Also, it can slow down your bowel movements.  As with any pain med, best to get along without it, but if you desperately need it sometimes then this is a huge relief."