If it's the same as amitriptyline, it made me feel tired, sick and headachey at first, but the side effects disappeared quickly, and helped my IBS so much i was prepared to see out the unwanted tiredness etc.I'm taking 20 mg before bed every night - originally it was 10mg but that dose wasn't doing quite enough.For me, it's been the only drug that has had any significant positive effect on my IBS.