A synthetic pyrazinoic acid amide derivative with bactericidal property. Pyrazinamide is particularly active against slowly multiplying intracellular bacilli (unaffected by other drugs) by an unknown mechanism of action. Its bactericidal action is dependent upon the presence of bacterial pyrazinamidase, which removes the amide group to produce active pyrazinoic acid. Pyrazinamide is an important component of multidrug therapy for tuberculosis.