Uses: This medication is used alone or with another medication to help prevent a certain serious infection (Mycobacterium avium complex-MAC). Rifabutin is known as a rifamycin antibiotic. It works by stopping the growth of bacteria. This antibiotic treats and prevents only bacterial infections. It will not work for viral infections (such as common cold, flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.