Lexithromycin is a semisynthetic antibiotic derived from erythromycin . Lexithromycin has improved absorption in vivo over erythromycin due to increased hydrophopicity and pH stability. As with other macrolides, lexithromycin prevents protein synthesis by binding the ribosome at the polypeptide exit tunnel. Formulations containing lexithromycin were tested in clinical trials as treatment for HIV but were discontinued.