According to both my PCP and pulmonologist, it is safe. I took it during antibiotice treatment for MAC.

Agree with Sue. I was started on it by first pulmonologist and was thought to have MAC. I was left on it by Mayo who also thought it was MAC while awaiting bronchoscopy cultures. When cultures were negative, they switched me to one they mix with different antihistamine and steroid.
Just make sure you use just the Azelastine, which is over counter. I think it also comes with a steroid. Good luck.