Tiamulin hydrogen fumarate is a semisynthetic derivative of pleuromutilin. Tiamulin is active against gram-positive bacteria, mycoplasmas, and anaerobes, including Brachyspira hyodysenteriae. It is also clinically effective in treatment of swine dysentery and mycoplasmal arthritis. Tiamulin is well absorbed when administered PO. The dosage is 8.8 mg/kg/day for 3–5 days, in either food or water. The parenteral dosage for mycoplasmal pneumonia in pigs is 15 mg/kg. In poultry, tiamulin interferes with monensin and salinomycin metabolism, and if the drugs are fed together, they become toxic. Generally, however, tiamulin has few adverse effects.
