Klacid IV is the internationally recommended first-line treatment for respiratory tract infections. Klacid IV is recommended by the American Thoracic Society (ATS), Infectious Disease Society of America (IDSA) and U.S. Center for Disease Control and Prevention (CDC). Most patients on Klacid IV feel better within 2 days of treatment & it offers wide coverage against most respiratory pathogens including gram+ve, gram-ve, and atypical pathogens. Ceftriaxone is used to treat a wide variety of bacterial infections. This medication is known as a cephalosporin. It works by stopping the growth of bacteria.