Ketamine has rapid effects in alleviating depression, and can do so in those with depression that has been resistant to other treatments.  This much has been known for 20 years.  Whilst esketamine nasal spray has been licensed, its cost and uncertain positioning in the pathway have prevented wide use. Racemi ketamine has not gained widespread use as an off-label antidepressant because it needs to be given repeatedly, IV administration is burdensome, and it has abuse potential.  In this talk, I will briefly review the evidence of benefit in TRD and other conditions, examine what is known of its mechanisms of action, and discuss the possibilities for implementation.