Nortriptyline
"I suffered with Irritable Bowel Syndrome for over 30 years beginning in my 30's after a severe gastrointestinal infection. I controlled it with OTC meds like Pepto-Bismol and Imodium. The condition worsened until I could no longer count on having a symptom free day and my diet was severely limited. My doctor recommended Nortriptyline and the lowest dose of 10 mg immediately worked. I now can eat a diet that includes fruits and vegetables I has been unable to eat for years. I did have one troubling side effect at first -rapid heart rate. I was taking a low dosage of a beta blocker for this condition prior to taking Nortriptyline. My doctor recommended increasing my beta blocked dosage, and the palpitations  have discontinued. I am healthy and very active."