People always vary in response to drugs.

Ultram (tramadol) has typically been a difficult drug.
It works for many, others cannot stand it.
Some like it so much they will even forge Rxs for it, and cannot discontinue it.

It works on mu receptors and has some SSRI SSNI reuptake functions.

Sometimes it is the metabolites from the drug that cause the problems. I looked around tonight and could not find much
in the way of nerve toxicity. I did find some side effects reported as paresthesias however. But many drugs have those.

Whatever was bothering you is real however. I am glad for you that you discovered this. Many people get on drugs for chronic conditions and fail to notice negative side effects when they occur. Your experience is a heads up for others here.

I'll give you this personal example:
About a year or so ago, my liver functions started to change. This was puzzling. You know
what it was? Claritin !! Good old Claritin for allergies! I stopped it when I quit my job, and
bingo, the liver functions came back down. They were never really high, just beginning to go up.
I looked everywhere for confirmation and couldn't find it. But I remember a forum member from
BT had a severe liver response to it and posted once about it. So drugs always have
a potential to be difficult for some.