Pyrazinamide acts on

(C) Tuberculous bacilli in macrophages # PYRAZINAMIDE A derivative of nicotinic acid, pyrazinamide is an important bactericidal drug used in short-course therapy for tuberculosis.> Mechanism of action: Pyrazinamide is similar to isoniazid in its narrow spectrum of antibacterial activity, which essentially includes only M.tuberculosis. The drug is bactericidal to slowly metabolizing organisms located within the acidic environment of the phagocyte or caseous granuloma; it is active only at a pH of <6.0. Pyrazinamide is considered a prodrug and is converted by the tubercle bacillus to the active form pyrazinoic acid. The target for this compound is thought to be a fatty acid synthase gene. Susceptible strains of M. tuberculosis are inhibited by 20p g/mL.