The role of low dosage prothionamide with and without 4,4'-diamino diphenyl sulphone for use with isoniazid in the treatment of experimental mouse tuberculosis.

To determine whether or not low dosage prothionamide (PTH), with or without diamino diphenyl sulphone (DDS), can replace PAS or thiacetazone as the companion drug to isoniazid (INH) in the treatment of tuberculosis, two experiments have been performed in mice. In experiment I the 2-month effectiveness of 25mg/kg INH alone, INH+PTH (25mg/kg) or INH+PTH+DDS (10mg/kg) was investigated. Both PTH-containing regimens were equally effective in preventing the selection of INH-resistant mutants but PTH did not appear to add much to the bactericidal activity of INH. In experiment II the one year effectiveness of similar regimens supplemented by an initial month of streptomycin (SM) was investigated. Again PTH appeared very effective whereas DDS seemed ineffective. Therefore it seems that PTH is likely to be a good companion drug for INH when used in man at the dosage of 5mg/kg which is more or less equivalent to 25mg/kg in the mouse.