Chromosomal aberrations in tuberculosis patients before and after treatment with short-term chemotherapy.

Cytogenetic effects of 4 common anti-tubercular drugs, isoniazid (H), streptomycin (S), rifampicin (R) and pyrazinamide (Z), in 3 different combinations (2 SHRZ, 2 HRZ and 2 H2R2Z2) were evaluated in the lymphocytes of tuberculosis patients undergoing chemotherapy, in order to estimate their mutagenic potential in combination. All 3 regimens showed an increased frequency of chromosomal aberrations after treatment compared to before treatment. These findings are of significance in the treatment of tuberculosis, as the drugs in question are observed to be mutagenic/clastogenic.