Hello.... I've been on and off Elavil for 20 years taking anywhere from 50mg to 300mg for chronic cluster headaches. New meds seem to work for a while, but I found myself asking to be put back on it, since it seems to be the only preventive medication that works. In 2010 I was referred to a pain management doctor who treats my headaches with Botox. I currently take 75mg of Elavil and 150 units of Botox every 3 months. The only downfall is the length of time it takes for Botox to work; 3 treatments and approximately 9 months. I tend to get frequent daily headaches, but they are tolerable and about 6 weeks of cluster headaches a year, which feels like a lifetime but better than 52 weeks that I dealt with for years. I never noticed any weight gain until I started to get Relief from Botox and became pain free.