Dosing regimens in the treatment of tuberculosis.

Specific antituberculosis chemotherapy started in the early 1940s. The development of isoniazid in 1952 enhanced the probability of achieving curative therapy. Introduction of rifampicin in the late 1960s and addition of the sterilizing agent pyrazinamide made it possible to shorten the length of treatment and to give it intermittently so that it could be fully supervised. The important principles to consider in the formulation of adequate therapy for tuberculosis are the different bacterial populations and drug resistance. The antituberculosis drugs vary in their bactericidal action, sterilizing action, ability to prevent the emergence of acquired resistance and suitability for intermittent use. The recommended regimen for newly diagnosed patients is a six month daily regimen of isoniazid and rifampicin, supplemented with pyrazinamide for the first two months. Variants of the standard six month regimen are used when fully supervised intermittent chemotherapy can be organised, when there is a high level of initial resistance or if it is suspected that the patient's strain is resistant to isoniazid. The recommended dosages are appropriate for all forms of tuberculosis and are the same for children and adults.