Tuberculosis second-line agents

Streptomycin is mainly used as a second-line agent for treatment of tuberculosis. The dosage is 0.5-1 g/d (7.5-15 mg/kg/d for children), which is given intramuscularly or intravenously. It should be used only in combination with other agents to prevent emergence of resistance. See Chapter 47 for additional information regarding the use of streptomycin in mycobacterial infections. 

Ciprofloxacin and ofloxacin are effective for gonococcal infection, including disseminated disease, and ofloxacin is effective for chlamydial urethritis or cervicitis. Ciprofloxacin is a second-line agent for legionellosis. Ciprofloxacin or levofloxacin is occasionally used for treatment of tuberculosis and atypical mycobacterial infections. They may be suitable for eradication of meningococci from carriers or for prophylaxis of infection in neutropenic patients. 

Aminosalicylic acid (PASER) is a second-line agent in the management of tuberculosis. It is administered orally in a daily dose of 10—12 g. Because of Cl irritation, it is administered after meals and divided into 2 equal portions. Children should receive 150-300 mg/kg/day in 3 divided doses. 

A number of drugs—aminosalicylic acid [a mee noe sal i SIL ik], ethionamide [e thye on AM ide], cycloserine [sye kloe SER een]— are considered second-line drugs because they are no more effective than the first-line agents and their toxicities are often more serious. Streptomycin, the first antibiotic effective in the treatment of tuberculosis, has been discussed wth the aminoglycosides (see p. 314). Its action is directed against extracellular organisms. 

This process was undoubtedly developed for the manufacture of pyrazinamide (Zinamide, etc.),1696 a second-line drug for Mycobacterium tuberculosis infections, resistant to more effective and less toxic agents. Thus a mixture of 2-methyl-pyrazine (323), ammonia, oxygen, and steam is passed (at 400°C) over an alumina- or pumice-supported catalyst comprising one to three oxides of Ce, Cr, Mo, Mn, P, Sb, Ti, or (most importantly) V the main product (in up to 90% yield) is 2-pyrazinecarbonitrile (324), easily converted into 2-pyrazinecarboxamide... 

Mycobacteria cause tuberculosis, Mycobacterium avium complex (MAC) disease, and leprosy. Tuberculosis remains the leading worldwide cause of death due to infectious disease. First-line agents for the chemotherapy of tuberculosis combine the greatest efficacy with an acceptable degree of toxicity (Table 47-1), and the large majority of patients with tuberculosis are treated successfully with these drugs. Occasionally, it may be necessary to resort to second-line drugs. 

Capreomycin resembles viomycin both chemically and pharmacologically. It is considered to be second-line antitubercular drug used in combination with other such agents. It is frequently used in place of streptomycin when either the patient is sensitive to it or the strain of M tuberculosis is resistant to it. 

Dartois, V., Barry, C.E., 2010. Clinical pharmacology and lesion penetrating properties of second-and third line antituberculous agents used in the management of multidnig-resistant (MDR) and extensively drug resistant (XDR) tuberculosis. Curr. Clin. Pharmacol. 5, 96—114. 

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