For moderately symptomatic disease due to MAC with positive sputum smears and cultures, clarithromycin 500 mg orally 2 times a day or azithromycin 600 mg orally once / day, rifampin (RIF) 600 mg orally once / day, and ethambutol (EMB) 15 to 25 mg / kg orally once / day should be used for 12 to 18 months or until cultures are negative for 12 months.