Ethionamide

Ethionamide is an antimycobacterial antibiotic that is active against M. tuberculosis (MICs = 0.3-1.25 µg/ml). Ethionamide is a prodrug activated via oxidation by ethA (a flavin monooxygenase) and leading to the formation of an soxide metabolite, which inhibits the InhA enzyme involved in mycolic acid biosynthesis. Formulations containing ethionamide have been used in the second-line treatment of multi-drug resistant tuberculosis. Ethionamide inhibits both biofilm formation and viability of mature biofilms. Ethionamide is a thioamide analog of the first-line tuberculosis drug isoniazid.