I have nebulized Tobi for many years. A year after starting it, a light tinnitus developed in both ears that over the years became more noticeable. There might be a causality here. Although little enters the bloodstream, some does and besides that it enters the mouth and throat from which there is a direct connection to the inner ear via the eustachian tube. So I don’t think it is absolutely safe for the ears to inhale it long term.
I also nebulized other antibiotics like Aztreonam (Cayston). No side effects to mention. No positive effects either. It was expensive however and took time.
Once I tried Tobi powder inhaler (podhaler) that caused an immediate inflammatory reaction with a slight fever, tiredness and shortness of breath.
I have never registered any change in the airway infection patterns or cultures from inhaled antibiotics. It was mostly prescribed to me to prevent future colonisation of PA, but if you are not colonized yet it is almost impossible to proof this claim directly. So in general I am not a fan of these sorts of preventive prescriptions. If you are colonized, the situation is different.
Since a couple of years I don’t use inhaled antibiotics anymore. I noticed no significant difference in the infection patterns or cultures after stopping. But my lungs seem more relaxed, less inflammation is going on. I am not convinced that, considering the trade off between the inflammatory and the antibacterial effect, starting inhaled antibiotics again is beneficial per se in my current situation.
I would use inhaled antibiotics again if there is an infection that could be cured by doing so only or much better than with systemic administration (also considering side effects), but if no clear result would present within a couple of weeks, I would not go on with it indefinitely.