Chemical Structure / Formula of Ethionamide
Formula: C8H10N2S
Structure: Similar to isoniazid but contains a thioamide (-CSNH₂) group instead of a hydrazide.
Mechanism of Action
Prodrug, activated by mycobacterial EthA enzyme.
Inhibits InhA enzyme, blocking mycolic acid synthesis, disrupting the bacterial cell wall.
Uses
Second-line drug for multidrug-resistant TB (MDR-TB).
Side Effects
Hepatotoxicity, neurotoxicity (peripheral neuropathy, psychosis).
GI disturbances (nausea, vomiting, abdominal pain).
Hypothyroidism (interferes with thyroid hormone synthesis).
