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)

Antibacterial agent used primarily as a tuberculostatic. It remains the treatment of choice for tuberculosis.

Isoniazid, drug used in the treatment and prevention of tuberculosis. Isoniazid commonly is used in combination with other drugs, such as rifampin, ethambutol, pyrazinamide, or streptomycin; these drugs are used with isoniazid in order to prevent, or at least delay, the development of...