Tiamulin

Tiamulin Full Name

Tiamulin

Tiamulin Introduction

Tiamulin, which is often used in the form of its fumarate salt (Tiamulin Fumarate), is a critically important semi‑synthetic derivative of the pleuromutilin class of antibiotics. Pleuromutilin itself possesses notable antibacterial activity, particularly a strong inhibitory effect against Gram‑positive bacteria. However, its poor water solubility, low bioavailability, and rapid metabolism in animals limited its potential for direct clinical use in veterinary medicine. Through systematic chemical modification of the pleuromutilin structure, researchers introduced a sulfur‑containing side chain—(R)-N,N‑diethylaminoethanethiol—at the C14 hydroxy group, successfully synthesizing tiamulin. This structural modification significantly improved the pharmacokinetic properties of the drug, enhancing its water solubility, oral absorption, and concentration in target tissues, while preserving and even broadening its antibacterial spectrum. Subsequently, to improve stability and facilitate formulation, it is commonly prepared as the fumarate salt. This successful semi‑synthesis established tiamulin as one of the first‑choice drugs in veterinary practice for treating and preventing infections caused by pathogens such as mycoplasmas and spirochetes.

Figure 1. Tiamulin hydrogen fumarate. (Source: Islam KM, et al. 2009)

Tiamulin exhibits excellent bactericidal or inhibitory activity against a range of animal mycoplasmas, often hailed as a "specific anti‑mycoplasma agent." This includes Mycoplasma hyopneumoniae (the cause of enzootic pneumonia in pigs), Mycoplasma hyosynoviae (associated with arthritis), Mycoplasma gallisepticum (causing chronic respiratory disease in poultry), and Mycoplasma meleagridis (the agent of infectious sinusitis in turkeys). Its importance is particularly pronounced because mycoplasmas lack a cell wall, rendering many cell‑wall‑targeting antibiotics (such as β‑lactams) ineffective.

Tiamulin also demonstrates potent activity against Brachyspira hyodysenteriae, the causative agent of swine dysentery, and Brachyspira pilosicoli, associated with intestinal spirochetosis in pigs. Swine dysentery is a disease that causes significant economic losses in the pig industry, and tiamulin is a classic and preferred treatment. Furthermore, it shows good activity against most aerobic and anaerobic Gram‑positive bacteria, including Staphylococcus, Streptococcus, Erysipelothrix (e.g., Erysipelothrix rhusiopathiae, the cause of erysipelas), and Clostridium species (e.g., Clostridium perfringens, involved in necrotic enteritis). It is noteworthy, however, that tiamulin has weak or no activity against most Enterobacteriaceae (such as E. coli and Salmonella) and Pseudomonas aeruginosa. This relatively narrow yet well‑targeted spectrum can be seen as an advantage, as it effectively treats the intended infections while causing relatively minor disruption to the beneficial gut flora (particularly Gram‑negative commensals), thereby helping to maintain intestinal microecological stability.

Alternate Names for Tiamulin

Tiamulin

• 1. Islam KM, et al. The activity and compatibility of the antibiotic tiamulin with other drugs in poultry medicine--A review. Poult Sci. 2009 Nov;88(11):2353-9.
  2. Stipkovits L, et al. Mycoplasmoses in poultry. Rev Sci Tech. 1996 Dec;15(4):1495-525.