irritable bowel syndrome
"I have IBS-C. My doctor switched me to 25mg of nortriptyline after complaining of constipation on 10mg amitriptyline. I've had practically no side effects compared to amitriptyline except worsening constipation. Have had to use miralax aggressively to counteract this but it works. No pains at all and has also helped with my anxiety! I'm sure it would work even better if I had IBS-D instead."