Results from a newly published study indicate that intranasal ketamine spray can produce a rapid and sustained antidepressant effect within 24 hours, and was well tolerated in a small group of patients with treatment-resistant major depressive disorder.
http://www.forbes.com/sites/robertglatter/2014/04/13/intrana...
Take a look into it, and best of luck!
The study in that forbes article used 50mg intranasally (basically snorted). The earlier study backing ketamine's efficacy[1] used "0.5 mg/kg diluted in saline, administered over 40 minutes by IV pump". Works out to 35mg for a 70kg guy with a drug delivery rate in the ballpark of snorting it.
Redosing protocol is up to you, I'd read both papers, track your mood, and decide something reasonable. [1] dumps a fair amount of K into their volunteers in one part. Basically the 35mg every two to three days. When depression hits hard I do 35mg every one or two weeks, and go up to 3 weeks as I'm feeling better.
I like dissociatives but maaan 35-50mg is pretty much the least pleasant dose. You're not near k-holing but reality is still pretty bent for about 45 minutes. Normal social interaction is totally out of the question for me and my thinking is warped. What works best for me to handle it is putting on an album I can play all the way through, lying down and meditating on the music until I sober up.
Cheers!