As a follow up to my earlier post, it has now been 2 weeks on Mexiletine (2 x 200mg/dy). During the first 4 days I experienced some gastric burning and wasnt sure how much longer I could continue. I started a 14 day run of Prilosec, which doesn't interact with the Mex. Also was taking 5-6 tums a day. I am now at about day 9 with the Prilosec which substantially reduced the gastric irritation, and have continued the Mex. At day 8, I began to sense a pretty noticeable benefit from the Mex. This was at the end of a weekend when I hadn't sat very much (a primary trigger of PN for me). This past week has been up and down so the jury is still out. However I found Mex to have more manageable side effects than neurontin or cymbalta, which was a terrible experience. My head remains clear and sharp - no foggy groggy stuff as I found with the psych drugs.