Nortriptyline
"Doc prescribed this after I'd been having a lot of stomach cramps followed by diarrhea after eating. I have mixed IBS and cycle between diarrhea and constipation. 

It worked but the side effects were a bit much It kept having mixed effects on my sleep. I either was wired all night or slept through my alarm. 

There didn't seem to be any buildup effect, if I missed a dose I was screwed for the next two days. Also noticed a decrease in my sex drive but my increase in episodes was definitely stress induced so who knows. 

Eventually the constipation got to be too much I will only take it if I'm having more diarrhea episodes. 

I'm still dealing with gas pain (which I think this medication may have helped with, not 100% sure) and constipation."