I have also had a headache with Pexeva, on and off for weeks, and even as a withdrawal symptom. I went back on after two days for various reasons. I mainly went off the med because it was making me have to go to the bathroom (soft stools, sometimes worse) and lots of gas and stomach cramps, etc. I decided to go back on though because I loved how calm and relaxed I was. I also had an awful headache like when I had first gone on the med. I believe it was withdrawal symptoms (even though I had just started Zolof). I thought if I went back on Pexeva, my gastrointestinal symptoms might disappear after a few weeks and I need to give it more time to see. I have been back on for 7 days now and have yet to achieve the calm and relaxed mood I was in, but maybe I need another week. The gastro problems are on and off, some days better than others. Headache has varied, but today the worst. The one problem I am having and perhaps is getting worse is itchy skin, especially my nose (on outside, top and around it). So, maybe I am allergic to Pexeva, which would explain also the gastro probs. All and all, I have probably been on this med for a couple of months or so, mostly on.