https://erowid.org/chemicals/ketamine/ketamine_article2.shtm...
I've taken about 1000mg over the course of several months, at irregular intervals. While it is somewhat higher than Scott's 280mg/month, it's not an order of magnitude higher. Certainly nowhere near 90,000mg/month.
I can report one event of pain while peeing, a few days ago. So it looks like my body is not built to handle even moderate levels of ketamine use, and I'd have to stay closer to 100mg/month or lower to be on the safe side.
That said, let me reiterate, this is anecdote. I only think it's interesting because there is no other reasonable explanation for my recent urinary pain, and I didn't expect such low doses of Ketamine to have noticeable effects.
Applied topically? Or in the sense that the anesthetic disassociative effects dull most sensations?
I took it insufflated, the short duration of action and general anesthesia makes it decently practical.
(Of course it sounds pretty silly to recommend Ketamine for a small everyday itch. But that's what I had on hand, and I happen to dislike mosquitos with a very particular intensity =] )