Another drug in the same category is Topamax - which is generic, so cheap and allowed. It works well for pain for me with some caveats, so read up on it and try out cautiously at tiny dose to start!
I love the pain efect of this drug, but I am wondering if I am having side effects from it or just from my sinus surgery. I never tolerate drugs well, so start on half or 1/4 the lowest available dose. For me that's 1/8 (awfully hard to cut) of the 50 mg pill, but it comes in 25 and 15, which I would say cut also. It's a little bitter but quite tolerable.
I am having tinnitus, food tasting bad, just had a bad tachycardia event which was precipitated by albuterol, but having small ones also even watching my diet for my other triggers, feel hot then cold, hot flushes. But I have a sinus infection going on too (call in to ENT). The effects could all be from sinus problems or the drug.
I get some relief from tramadol and tiny help from Tylenol which potentiates a bit.
My hand doc said try 100 IU B-6 a day for nerve pain. Virtually ALL vitamins have only tiny amount, so look for B-100, which also has B-12 but is a little large for me, or straight B-6 100 IU.