Valnemulin (marketed under the trade name Econor) is a pleuromutilin antibiotic used to treat swine dysentery, ileitis, colitis and pneumonia. It is approved for veterinary use only. Valnemulin is an antibiotic belonging to the pleuromutilin group, which acts by the inhibition of the initiation of protein synthesis at the level of the bacterial ribosome. Valnemulin has activity against a range of bacteria including those responsible for enteric and respiratory disease in pigs. Valnemulin shows high activity against Mycoplasma spp. and spirochaetes such as Brachyspira hyodysenteriae and Brachyspira pilosicoli. Valnemulin has little activity against Enterobacteriaceae, such as Salmonella spp. and Escherichia coli. There appears to be no resistance development to valnemulin to date by M. hyopneumoniae and L. intracellularis. There have been some increases of MICs of valnemulin against B. hyodysenteriae and to a lesser degree B. pilosicoli, some of which appear to have developed resistance. Valnemulin binds to the ribosome and inhibits bacterial protein synthesis. Resistance development primarily occurs because of changes at the binding site associated with mutations of the ribosomal DNA genes. Econor 10% and 50% is indicated for: The treatment and prevention of swine dysentery. The treatment of clinical signs of porcine proliferative enteropathy (ileitis). The prevention of clinical signs of porcine colonic spirochaetosis (colitis) when the disease has been diagnosed in the herd. Treatment and prevention of swine enzootic pneumonia. At the recommended dosage of 10 - 12 mg/kg bodyweight lung lesions and weight loss are reduced, but infection with Mycoplasma hyopneumoniae is not eliminated. Econor 0.5% and 1% is indicated: For the treatment and prevention of swine dysentery. The treatment of clinical signs of porcine proliferative enteropathy (ileitis). The prevention of clinical signs of porcine colonic spirochaetosis (colitis) when the disease has been diagnosed in the herd.