Amitriptyline did give me constipation. It made me pee a lot more too. I don't tend to get IBS symptoms a lot though. Just minor phases of a few days here and there. I see mine as more of "it's my guts that are having a bad ME time" rather than it being IBS per se. You'd need to think carefully. Looking back, it was worth it for me, despite the problems. I got some sleep. When I stopped them, the lack-of-sleep cycle had been broken. If somebody has any hint of addiction to benzos, never, ever take them. EVER. I was prescribed them like sweeties in the '70s, came off cold turkey, and quite frankly, have lost several years of memories of what was going on. I did have to resort to valium once in later years, for utterly exceptional circumstances, just for a few weeks, and again, was forced to come off far too soon and far too fast. Have you ever considered cannabis? I don't know where you are or if it would be obtainable legally.