Over a year ago I was taking Amitriptyline, 20 mg at night. I went off of it when i found out that it may cause weight gain. Now I agreed to try it because of the horrible pain I am in and the fact that I am not responding to alot of drugs, especially for my RLS. (BTW, I also just started Mirape) I was wondering if anyone can pinpoint what it is exactly that causes the weight gain? Is it the medication itself, or is it hunger caused from the medication?