Erythromycin.

Erythromycin is the only macrolide antibiotic to have gained widespread use in the United States. Introduced in 1952, it rapidly gained a popularity that it enjoys to this day. Numerous other antimicrobial agents have been marketed since that time: Whole new classes of antibiotics, both natural and synthetic, have been discovered, studied, and released for general use. Many of these newer agents boast a broader spectrum of antimicrobial activity, yet erythromycin's place in the clinician's arsenal is unthreatened because erythromycin remains the drug of first choice for a number of pathogens against which the new drugs are inactive. It is one of the safest antibiotics available for use today and when used against susceptible organisms and in indicated clinical situations, its effectiveness is unquestioned.