This drug has an antimicrobial spectrum similar to that of azithromycin. The structural modification within ketolides neutralizes the most common resistance mechanisms (methylase-mediated and efflux-mediated) that make macrolides ineffective. It has excellent activity against resistant organisms. Side effects include possible liver damage. Approved for oral treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis, and acute bacterial sinusitis in adults. Expensive, may cause transient visual disturbances, an Inhibitor of CYP3A enzymes, and should not be used in patients with myasthenia gravis.