Tildipirosin is a semisynthetic derivative of the naturally occurring 16-membered macrolide tylosin. Tildipirosin is intended for parenteral treatment of respiratory disease in cattle and swine. Tildipirosin will be administered as a single-dose injection: subcutaneously in cattle and intramuscularly in swine. The anticipated optimal clinical dose is 4 mg/kg bw. Tildipirosin is not used in human medicine. It is marketed under the brand name Zuprevo. As for other macrolides, the antimicrobial activity of tildipirosin is due to its binding to the ribosomal 50S subunit of bacterial cells thereby inhibiting bacterial protein synthesis. The in vitro antimicrobial activity against Gram-negative and Gram-positive pathogens indicates that tildipirosin is effective against a range of bacterial pathogens frequently associated with bovine and swine respiratory disease. Comparison of minimum inhibitory versus bactericidal concentrations shows that generally the antimicrobial action of tildipirosin is bacteriostatic.