it works orally as well, but its a waste, takes lots. And many people enjoy k-holes as well. Personally, the stuff gives me a headache. I could see it being used for pain. Nitrous too.

There are several experiments using it as an adjunct to opioids... not sure how much it is done in practice. This page has a little info and is referenced: http://www.medicineau.net.au/clinical/palliativecare/ketamine.html