One year ago Ketamine was given orphan drug status by the FDA, for the treatment of CRPS. I’ve had three rounds of five two-hour ketamine infusions over the past year. The second series resulted in 45 days without my CRPS pain. Here’s some info from the Cleveland Clinic:
https://health.clevelandclinic.org/when-nothing-seems-to-help-your-crps-ketamine-pain-treatments-may-bring-relief/amp/