Judy, I am a retired small animal Veterinarian, favorite dog breed Standard Poodle, having raised several AKC litters over the years.
I have been on Arikayce for 7 weeks now after getting a positive culture for MAC after taking the big 3 for over 6 months. The only symptom I have is a mild ringing in my ears. Was tested by an Audiologist and I do not have any hearing loss so unless the tinnitus gets worse I will continue taking the Arikayce. I believe IV Amikacin is one of the better drugs for MAC but it has a lot of potentially serious side effects. Taking it by inhalation allows for a smaller dose to get the desired effect with a lot fewer side effects. The "pink plugs" you refer to are probably from small amounts of blood due to the direct irritating effects of the drug, you might ask your Dr about that. My own sputum has been the same for 4 years (light brown), my Dr says the color is probably due to the underlying bronchiectasis that I have. The fact that your sputum is mostly clear is probably a good thing. After the drug kills the MAC it is likely absorbed by the lungs or possibly coughed up but there is no way you can actually see the dead bacteria.
I would be contacting your doctor asap about when to submit a sputum sample, I would think after taking the drug for 3 months it is time to do that. Good luck to you. Bill