Rifampicin Isoniazid is a combination drug that is composed of two drugs which treat tuberculosis, isoniazid and rifampicin.
Rifampicin is a derivative of rifamycin that hinders the formation of bacterial RNA by binding to RNA polymerase, further repressing the connection of the enzyme to the DNA, blocking RNA elongation and transcription. It has bactericidal activity against tubercle bacilli.
Isoniazid is a drug that is also used to treat tuberculosis. It inhibits the formation of the cell walls of the tubercle bacilli, further killing them.