irritable bowel syndrome
"I also took nortriptyline for irritable bowel syndrome.  It did work within a couple of days, however it also came with side effects.  I would wake in the middle of the night and not be able to go back to sleep. The worst side effect was a marked decrease in sexual performance.  I discontinued the medication after two weeks.  Within a few days the IBS was back, but the side effects were gone."