Hello Irene, Cayston is currently approved for Cystic Fibrosis patients, and classified as a specialty drug. There were clinical trials using Cayston in patients with bronchiectasis, but I think they were inconclusive as to whether the results were good enough to justify the side effects. So as of now, it would probably be managed by doctors and insurance as an "off label use" for those who standard treatments did not help.
Here is a report of one trial that reports the type and frequency of side effects. A list of the abbreviations is at the end of the article so you can figure out what it all means. Sorry I couldn't find a report in layman's language that we could all understand more easily!
cayston-use-in-bronchiectasis-not-related-to-cystic-fibrosis-ncfb-.pdf

Has a doctor suggested you try Cayston? Maybe you will be the first in this group and can share your experience with us!
Sue

@irenea8 I have bronchiectasis. I have had pseudomonas aeruginosa for several years. The PA doesn’t always show up in sputum cultures but it has enough times that most antibiotics I have taken don’t completely get rid of it. The oral antibiotics I have tried in the last four years are Cipro, Levaquin, Bactrim and Augmentin. IV antibiotics included Cefapime twice a day for 28 days (but 3 weeks in I developed a rash so had to stop) and Meropenem, 3 times a day for 28 days. I used nebulized Tobramycin for 19 months (2 weeks on, 2 weeks off). Tobi was hard to tolerate so was changed to Cayston, 2 weeks on, 2 weeks off. And yes it was very expensive. Medicare considers it a tier 5 specialty drug and has to be obtained through a specialty pharmacy. My secondary insurance approved it, but my copay was awful. I used Cayston for 9 months but it was so expensive and towards the end of the 9 months it wasn’t helping so I went back to Tobramycin for 4 months. After that and currently, I have been taking nebulized Colistin (for 11 months). It is twice daily. It has helped the most of anything recently. I am coughing a lot less, and cough up very little sputum. I would like to add that my regimen for the last four years include a compound nose spray, Advair 500, sodium chloride 7% or 3%, airway clearance vest (all of those 2 times a day). I also attend pulmonary rehab 3 times a week. I have been under the care of the same Mayo Clinic pulmonologist for 18 years. My first appointment there I was diagnosed with MAC and went through the 3 drug treatment, followed by 3 rotating antibiotics. I have had no MAC show up in sputum cultures since ending treatment. This may be more information than you were after, but felt it necessary to lead up to taking Cayston. Good luck with your treatment.