@sueinmn Thanks for your response Sue. There are at least 2 fairly lengthy discussions (I'm sure there are a lot more) about NAC (aka N-Acetyl cysteine, aka Mucomyst) on Lung Matters dating back quite awhile. It appears that five years ago the admin supported the use. Then later started debating pros and cons, and more recently, they have been non-supportive. There were a couple of links to studies, but when I clicked them (only have FB on my phone) my phone software cautioned me that I was leaving the site and uncertain of the safety of the new siteintapl.sc, so I didn't pursue.
In a discussion on LM on Dec 20, 2024 entitled "Questions about N-Acetyl Cisteine (NAC) there are links to 3 studies and the admin made comments about the findings: "to be precise, N-acetyl cysteine (NAC reduces ciliary beats, which slow innate airway clearance. Reduced risk airway clearance, together with the higher concentration of antibiotics needed to eliminate infections, makes the mucus thinning properties of NAC far inferior to hypertonic saline. In effect, NAC may significantly lead to more severe drug resistance". This is just a short excerpt from a much more involved discussion. They are saying that NJH no longer endorses NAC. I am sorry that I can't cut and paste these studies from my phone (I'm not techie). Many studies are cited. Here is a shorter link I typed out. If I can figure out how to cut and paste, I will send more.
https://intapl.sciendo.com/pdf/10.1515/afpuc-2017-0002