It's been over ten years dealing with LAR Syndrome, I've been to multiple specialists, with very little improvement to show for it. Finally, something that's helped a bit. A couple of months back, I had a bad episode of explosive diarrhea lasting over a week. The symptoms were different from what I've experienced before. I thought it could indicate I had an ongoing giardia infection that I had adapted to, but for some reason had it flare up. My new primary care doctor is much more willing to listen than my previous one and agreed to try one dose of tinidizaole, which is a newer drug used to treat it. It has definitely done something. The diarrhea stopped and there was a gradual but noticeable improvement in the LARS symptoms. It's not a miracle, but perhaps a 10-20% improvement. Less time sitting on the toilet, fewer visits to the bathroom with reduced urgency after meals, also much more normalized stool formation with less fragmentation. After two months, the improvement is still there.
Before cancer, I used to backpack, camp, and do international travel a lot. I got traveler's diarrhea many times but always recovered quickly. One of those times could have been a giardia infection. It's estimated that between 3 and 7 percent of the US population has an ongoing infection they've adapted to. It's worth discussing a course of this drug with your doctor if your LARS includes bouts of diarrhea, bad stool fragmentation, and lots of cramping that requires spending a long time in the bathroom. It cost me only $7 on my insurance and I am very glad I tried it.