Pharmacotherapeutic group: Antibiotic for dermatological use, other antibiotic.
ATCvet code: QD06AX
Pharmacodynamic properties
Thiamphenicol is a broad-spectrum antimicrobial agent, structurally similar to chloramphenicol. It is bacteriostatic for both Gram-positive and Gram-negative bacteria and acts by blocking the protein synthesis.
The most common mechanism of resistance to thiamphenicol is acquired by micro-organisms via a plasmid-encoded acetyltransferase that inactivates the drug. Cross-resistance of thiamphenicol with chloramphenicol is complete in bacteria which possess chloramphenicol acetyltransferases (CATs). Acetylation of the hydroxyl groups by CATs prevents drug binding to the 50S ribosomal subunit. There are also other mechanisms of resistance, such as efflux systems, inactivation by phosphotransferases, and mutation of the target site or permeability barriers. The CAT genes are commonly found on plasmids and most of these plasmids carry one or more additional resistance genes.
Pharmacokinetic properties
The absorption of thiamphenicol following dermal administration is negligible.