As a part of a research grant during fellowship, for CRPS/refractory neuropathic pain we did a 5 day Ketamine infusion program with higher daily titrated doses (10 mg/hr increased slowly to 20 mg/hr for 5 hours daily). About 30 patients throughout the year.
Rarely we had a good outcome, like maybe 5-8% for pain improvement for 30 days, mostly 1-2 days pain improvement 15% or no improvement after 5 days ~ 80% patients. Pretty much seemed like a waste of resources. Not a fan anymore...