Isoniazid mechanism

Isoniazid (INH) is a structural congener of pyridoxine. Its mechanism of action involves inhibition of the synthesis of mycolic acids, essential parts of mycobacterial cell walls. It is a prodrug that is activated by a mycobacterial catalase-peroxidase (KatG). It inhibits enoyl acyl carrier protein reductase (InhA) and a β-ketoacyl-ACP synthase (KasA) within the unique Type II fatty acid synthase system for mycolic acids. INH is bactericidal for actively growing tubercle bacilli, but is less effective against dormant organisms.