I can't say that I've seen the "can't drive" bit and certainly not been told it. For me, Letrozole exacerbates fatigue but in itself, doesn't make me drowsy. I take mine in the morning (only time I can be sure I'll remember) and don't have an issue - by the end of a day at work however, I am shattered. Had you noticed PN before starting the Letrozole? I was on something (who knows what it was) to help deal with the pain from the meds which had me dropping things all the time but the actual Letrozole hasn't caused it. Do check though.
