Kay I feel your pain with the cramping/diarrhea. For me it turned out to be a side effect of the Azithromycin. What I do is take 1 Imodium pill on an empty stomach at least 1 hour before taking the Azithromycin and that solved my problem. (you might try 2 Imodium to start just in case) I also had issues with Rifampin and stopped that. Still taking Ethambutol. My doctor who has connections with National Jewish Health stated Rifampin was likely not very important in MAC treatment. Good luck to you. Bill