Letrozole
"I've been on letrozole for a year.  After doing preliminary research about it, I really didn't want to go on it, but felt I had to give it a try.  The most serious SEs for me were severe joint pain and feeling frail; mood swings, and strong hot flashes.  The first 2 were bad enough that, after being on the drug for 8 months, I decided to take a break from it.  I went off for 3 weeks, then started back, but now I take it at night before bed.  I also started walking to keep weight gain at bay.  Since making those 2 changes, I've had no more joint pain or mood swings, and I feel healthier than I have in a long time.  Still have hot flashes, but they're tolerable.  I'm not sure why those changes would make that much difference, but they do."