{Reference Type}: Introductory Journal Article {Title}: Omadacycline: A Modernized Tetracycline. {Author}: Gallagher JC; {Journal}: Clin Infect Dis {Volume}: 69 {Issue}: 0 {Year}: 08 2019 1 {Factor}: 20.999 {DOI}: 10.1093/cid/ciz394 {Abstract}: When tetracyclines were introduced in the 1940s, these antibiotics offered a broad spectrum of activity against multiple types of pathogens. However, their utility waned after the selection of tetracycline resistance in the pathogens against which they were effective. Omadacycline is a semisynthetic aminomethylcycline antibacterial derived from the tetracycline class of antibiotics that is unaffected by these resistance mechanisms. It has an appropriate spectrum of activity for community-acquired infections, including those caused by many resistant organisms. Omadacycline offers a well-tolerated treatment for acute bacterial skin and skin structure infections and community-acquired bacterial pneumonia. Omadacycline has minimal known drug-drug interactions, and should be administered in a fasting state, avoiding dairy and cation-containing products for at least 4 hours after dosing. It does not require dose adjustments for sex, age, or hepatic or renal impairment, and has a safety profile similar to that of other oral tetracyclines. Because omadacycline can be administered effectively orally, it can help reduce hospitalization costs associated with intravenous antibiotic administration. This special supplement to Clinical Infectious Diseases offers an in-depth examination of omadacycline development, including discussions of pharmacokinetic and pharmacodynamic trials, spectrum of activity and preclinical data, early clinical trials, phase III clinical trials, and an integrated safety summary.