The first few years I was on it I would lose my voice about one week into my treatment. My voice would then be completely out for a week. I also experienced the "TOBI cough" which is that nagging, top of your throat non productive cough all day long.
Now that I'm older and my disease has progressed, or maybe I just developed new side effects, I cannot tolerate TOBI anymore. It makes me feel tight and my FEV1 actually drops significantly while on it, I have severe shortness of breath. I choose not to use TOBI anymore.