NCIt definition : A synthetic derivative of nicotinic acid with anti-mycobacterial properties. Although
its mechanism of action is still unclear, isoniazid appears to block the synthesis
of mycolic acids, major components of the mycobacterial cell wall. This agent is only
active against actively growing mycobacteria because, as a pro-drug, it requires activation
in susceptible mycobacterial species. Isoniazid also interferes with mycobacterial
metabolism of vitamin B6. Resistance occurs due to decreased bacterial wall penetration.
(NCI04);