Mucinex question about taking with upper respiratory infection?

have been sick with URI for last 5 weeks. Currently I'm on prednisone, Tylenol 3, phenergan, and protonix. Is mucinex ok to take along with them?? I have been sick for so long and am about to try anything and want to avoid having to go to pulminologist which is where I have to go next if the steroid doesn't clear it up. I have been on antibiotics and narcotic cough syrup and my pcp (understandably) doesn't want to keep me on both if they're not really helping.