isoniazid (Nydrazid, Laniazid, INH are all discontinued brands)

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DRUG CLASS AND MECHANISM: Isoniazid is an anti-bacterial drug that has been used to prevent and to treat tuberculosis since 1952. Tuberculosis is an infectious disease caused by a bacterium. Once the infection is acquired, it usually remains dormant in the lungs for up to many years. Later, the infection may become active in the lungs and sometimes spreads throughout the body. Patients with a tuberculosis skin test that has recently become abnormal (demonstrating recent infection with tuberculosis) but a normal chest X-ray (demonstrating inactive infection) are given Isoniazid alone for 9 months. Patients with active infection on chest X-ray are given Isoniazid combined with other antituberculous drugs. The mechanism of action of Isoniazid is not known, but it is thought to work through its effects on lipids (fats) and DNA within the tuberculosis bacterium. It is very selective for the tuberculosis bacteria, that is, it has few if any effects on other bacteria.

Medically Reviewed by a Doctor on 2/11/2015

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