I was on letrozole for a month. I developed eight side effects but none of the pain in the bones that are so common. Terrible G.I. issues or among the worst. The doctor took me off it for an AI holiday and they expect to put me on another one in about a month. I am now four months out from having stopped the AI and though some symptoms have subsided other symptoms have continued to ramp up, and I have continued to develop new symptoms. Recently my hair has started to fall out. Internet research indicates that when you stop an AI, the symptoms can continue to ramp up for around six months, but some symptoms for some people never go away.