Isoniazid infection

Aiititubercular drug s are used in combination with other aiititubercular dm to treat active tuberculosis. Isoniazid (INH) is the only aiititubercular drug used alone While isoniazid is used in combination with other drains for the treatment of primary tuberculosis, a primary use is in preventive therapy (prophylaxis) against tuberculosis. For example, when a diagnosis of tuberculosis is present, family members of the infected individual must be given prophylactic treatment with isoniazid for 6 months to 1 year. Display 12-1 identifies prophylactic uses for isoniazid. 

Isoniazid Daily for 9 monthsc,d In human immunodeficiency virus (HlV)-infected patients, isoniazid may be administered concurrently with nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors, or non-nucleoside reverse transcriptase inhibitors (NNRTIs). A (II) A (II)... 

Isoniazid Daily for 6 monthsd Not indicated for HIV-infected persons, those with fibrotic lesions on chest radiographs, or children. B (I) C (I)... 

Rifampin Daily for 4 months For persons who are contacts of patients with isoniazid-resistant rifampin susceptible TB. In HIV-infected patients, protease inhibitors or NNRTIs generally should not be administered concurrently with rifampin rifabutin can be used as an alternative for patients treated with indinavir, nelfinavir, amprenivir, ritonavir, orefavirenz, and possibly with nevirapine or soft-gel saquinavir5 B (II) B (III)... 

Administer pyridoxine (vitamin Be) 25 to 50 mg daily or 50 to 100 mg twice weekly to all HIV-infected patients who are undergoing tuberculosis treatment with isoniazid to reduce the occurrence of isoniazid-induced side effects in the central and peripheral nervous system. 

Intended for use concomitantly with other antituberculosis agents in pulmonary infections caused by capreomycin-susceptible strains of Mycobacterium tuberculosis, when the primary agents (eg, isoniazid, rifampin) have been ineffective or cannot be used because of toxicity or the presence of resistant tubercle bacilli. Administration and Dosage... 

Treatment of latent tuberculosis infection (LTBI) with isoniazid (INH) is very effective in preventing persons infected with M. tuberculosis from developing tuberculosis, regardless of HIV-1 serostatus. Several recent studies have shown that rifampicin and pyrazinamide taken for 2 months is as effective as 6-12 months of INH for the prevention of active TBC in HIV-1 seropositive persons although more hepatotoxicity is seen. 

There is evidence showing the efficacy of TBC preventive therapy among HIV-infected people. TBC preventive therapy can be given to people with HIV who have been screened to exclude active TBC and who are PPD positive. Isoniazid is the recommended drug. A dose of 5 mg/kg (maximum 300 mg) may be given daily as self-administered therapy for 6 months. 

Rifampin is a first-line antitubercular drug used in the treatment of all forms of pulmonary and extrapul-monary tuberculosis. Rifampin is an alternative to isoniazid in the treatment of latent tuberculosis infection. Rifampin also may be combined with an antileprosy agent for the treatment of leprosy and to protect those in close contact with patients having H. influenza type b and N. meningitidis infection rifampin is also used in methicillin-resistant staphylococcal infections, such as osteomyelitis and prosthetic valve endocarditis. 

Quinolones are important recent additions to the therapeutic agents used against M. tuberculosis, especially in MDR strains. Clinical trials of ofloxacin in combination with isoniazid and rifampin have indicated activity comparable to that of ethambutol. In addition, quinolones, particularly ciprofloxacin, are used as part of a combined regimen in HIV-infected patients. 

Rifampin, usually 600 mg/d (10 mg/kg/d) orally, must be administered with isoniazid or other antituberculous drugs to patients with active tuberculosis to prevent emergence of drug-resistant mycobacteria. In some short-course therapies, 600 mg of rifampin are given twice weekly. Rifampin 600 mg daily or twice weekly for 6 months also is effective in combination with other agents in some atypical mycobacterial infections and in leprosy. Rifampin, 600 mg daily for 4 months as a single drug, is an alternative to isoniazid prophylaxis for patients with latent tuberculosis only, who are unable to take isoniazid or who have had exposure to a case of active tuberculosis caused by an isoniazid-resistant, rifampin-susceptible strain. 

Isoniazid Inhibits synthesis of mycolic acids, an essential component of mycobacterial cell walls Bactericidal activity against susceptible strains of M tuberculosis First-line agent for tuberculosis treatment of latent infection less active against other mycobacteria Oral, IV hepatic clearance (half-life 1 h) reduces levels of phenytoin Toxicity Flepatotoxic, peripheral neuropathy (give pyridoxine to prevent)... 

Tuberculosis Persons with positive tuberculin skin tests and one or more of the following (a) HIV infection, (b) close contacts with newly diagnosed disease, (c) recent skin test conversion, (d) medical conditions that increase the risk of developing tuberculosis, (e) age < 35 Isoniazid, rifampin, or pyrazinamide Excellent... 

Oral contraceptive tablets are used to prevent pregnancy. Isoniazid may be used to prevent the development of active tuberculosis in those individuals who have been exposed to the disease but show no evidence of infection, in those who test positively for it but have no apparent disease, and in those with once active but now inactive disease. 

Rifampin [RIF am pin], derived from the soil mold Streptomvces. has a broader antimicrobial activity than isoniazid and has found application in the treatment of other bacterial infections. Because resistant strains rapidly emerge during therapy, it is never given as a single agent in the treatment of active tuberculosis. 

Correct choice = D. Isoniazid reacts with pyri-doxine (vitamin Be), which can cause a deficiency of this vitamin, isoniazid readily penetrates into infected cells and therefore is effective against bacilli growing intracellulariy. Isoniazid inhibits the metabolism of phenytoin. 

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