Isoniazide
Isoniazide, also known as isoniazid (INH), is a first-line antibiotic used to treat active tuberculosis and to prevent tuberculosis in people with latent infection. In active disease, it is given as part of a multi-drug regimen, typically with rifampin, pyrazinamide, and ethambutol during the initial intensive phase, followed by continued therapy with isoniazid and possibly other drugs for several months depending on the regimen and infection status. For latent infection, isoniazid alone or as part of a short-course regimen is used to reduce the risk of progression to active disease.
Mechanism of action: Isoniazid is a prodrug activated by the Mycobacterium tuberculosis catalase-peroxidase enzyme KatG. Once
Pharmacokinetics: The drug is well absorbed orally and distributes widely, including into the central nervous system.
Adverse effects and safety: Hepatotoxicity is the major concern, with risk increasing with age, preexisting liver
Interactions and monitoring: Co-administration with rifampin can raise the risk of liver injury. Alcohol use and