Small molecule
PubChem CID 3767
Isoniazid
Nydrazid
- Mechanism of action
- Isonicotinic acid hydrazide, inhibits mycolic acid synthesis (antimycobacterial)
- In plain language
- Blocks the tuberculosis bacterium from building a critical waxy layer in its cell wall called mycolic acid, which kills the bacteria as they try to grow and divide.
- How it works
- Isoniazid (isonicotinic acid hydrazide) is a first-line antimycobacterial agent. Per the FDA label, isoniazid inhibits the synthesis of mycolic acids, an essential component of the mycobacterial cell wall, and is bactericidal against actively growing intracellular and extracellular Mycobacterium tuberculosis organisms. Resistance can arise through mutations in several genes and develops rapidly if isoniazid is given as monotherapy against active disease, which is why it is always used in combination with other antituberculosis agents for treatment of active infection.
- Therapeutic applications
- Isoniazid is FDA-indicated for all forms of tuberculosis in which the organisms are susceptible, always in combination with other antituberculosis agents for active disease, since single-drug treatment is inadequate therapy. It is also indicated as preventive therapy for tuberculous infection in specified higher-risk groups, including persons with HIV infection and close contacts of persons with infectious tuberculosis. Its original brand, Nydrazid, is no longer marketed, but the drug remains widely available generically. The label carries a prominent warning that severe and sometimes fatal hepatitis has been reported with isoniazid, with risk increasing with age and with daily alcohol use, recommending monthly clinical monitoring and, for patients 35 and older, periodic liver enzyme testing.
- Class
- Small molecule
- Therapeutic area
- Antibiotic
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