Yes my experience with IV ketamine wasn't very good. Being on the drug was pleasant but after it left my system the payback was quite uncomfortable and bizarre. But that was just my own personal experience.
Goldstein infused ketamine at least a thousand times according to his own estimation. One thing he did stress time and time again whenever he mentioned his use of IV ketamine for CFS patients was to make sure the drug was mixed in 500 ml of normal saline and infused very slowly over at least 3 hours. Any faster and you ran the risk of adverse effects and in his experience if this occured, the drug would not work for you again. I actually walked out of two pain clinics before finding an appropriate one, because they wanted to infuse me in 45 minutes and declined my request to stretch the infusion to 3 hours. Just a caveat.If you look at Dr Goldstein's book, he administered ketamine orally, intranasally and even in the eyes (conjunctivally), and he talks about its effects on the trigeminal nerve (which runs to the face, mouth, teeth nasal and sinus cavities). I am not sure if Goldstein also performed ketamine IVs, but I am guessing these might work in a different way to when ketamine is used more locally to target the trigeminal nerve.