Clonidine
"I was prescribed this as I could not take HRT as I have had breast cancer.  tt was totally effective in stopping my hot flushes, and I couldn't have gont to work without it.  I was on it for a few years, but I don't need to take it anymore, now I'm 63.  I wasn't warned of any side effects, so I don't know if my slightly drier eyes (I wear contact lenses) and my migraines which I think got worse for a time, were due to my age or stress, or what.  But it was an absolute godsend for hot flushes, and I wasn't aware of any other side effects."