Hello @rosnat, I am answering you within a different discussion that is more current, so others are more likely to see and reply.
You wrote, "Hello my name is Rose I was just diagnosed with Mac about 1 month ago. I am 73 and I also have COPD. My dr. who is infectious disease Dr. put me on Clarithromycin 500mg 2 x a day and Rifampin 2 a day but for 7 days a week. Only after two days my stomach is a mess and also am having trouble falling asleep at night since starting these meds. It feels like what they call restless leg syndrome and I never had that before. I take 5mg of Ambien each night, have been for years because of insomnia . My question is most everyone is saying they are taking 3 different drugs not 2 and they only have to take them 3 days a week. Does anyone else have to take them everyday and he said I will be taking them for 2 years.? I can not imagine feeling this bad for years. He said my CT looked good other than the COPD no lesions or nodules so we caught it right away. Is anyone else having trouble with their legs when they go to bed or unable to fall asleep?"

I am really curious about your doctor's choice as well. It sounds like perhaps protocols are different for people with COPD. Or the specific strain of MAC you have may have been shown to respond better to this regimen. Or he may not have a great deal of experience with treating MAC infections.

Can you ask him why he chose the options he did? Feel free to refer to this document to learn more about treatment protocols:
https://www.lung.org/lung-health-diseases/lung-disease-lookup/nontuberculous-mycobacteria/learn-about-nontuberculosis-mycobacteria
Or to this treatise if you enjoy wading through scientific documents :
https://ntminfo.org/wp-content/uploads/2020/07/NTMguidelines2020.pdf
As always, the members here are happy to support you, and help answer questions, but some need to be addressed directly to your doctors.
Sue