What is isoniazid used for?

TB infection: Isoniazid (inh) chemoprophylaxis is preventive therapy for a subclinical tuberculous infection (+tb skin test) to prevent reactivation disease. Recommendations of the american thoracic society and the centers for disease control that all tuberculin skin test reactors between ages 21 and 35 years with no other risk factors should receive inh for 6-12 months.

See below:: Isoniazid is used alone or with other drugs to treat tuberculosis (TB) and to prevent it in people who have had contact with tuberculosis bacteria. It eliminates only active (growing) bacteria. Since the bacteria may exist in a resting (nongrowing) state for long periods, therapy with Isoniazid (and other antituberculosis drugs) must be continued for a long time (usually 6-12 months).