Hi @jeffrap, There are a few discussions on the topic that might be helpful.

--- Lidocaine or Ketamine Infusions: https://connect.mayoclinic.org/discussion/lidocaine-or-ketamine-infusions/
--- Anyone undergo routine ketamine infusions for SFN?: https://connect.mayoclinic.org/discussion/ketamine-infusion/
--- ketamine infusion and topamax??
https://connect.mayoclinic.org/discussion/ketamine-infusion-and-topamax/
At one of the meetings of the Minnesota Neuropathy Association before it disbanded there were a few members that were using a compounded topical that contained ketamine along with THC and found it helpful. They had to have it specially made at a compounding pharmacy. Are you thinking about infusions are searching for a topical medication?