Isoniazid resistance among new cases of sputum smear positive pulmonary tuberculosis

Aim: to determine the frequency of primary drug resistance to isoniazid among new cases of sputum smear positive pulmonary tuberculosis. methods: one hundred and sixty nine newly diagnosed patients with sputum smear positive pulmonary tuberculosis from jinnah hospital and lahore general hospital were enrolled and sputum culture and sensitivity was tested by standard laboratory method. patients with history of comorbid conditions and chronic steroid use were excluded. results: mean age was 31.63±8.7 years and 82(48.5%) among included persons were male and 87 (51.5%) were female. frequency of resistance to isoniazid came out about 20.1% while 79.9% persons were found sensitive to isoniazid. thirteen patients (7.7%) were found resistant to rifampicin too. there is no effect of gender or age in both groups with and without resistance to isoniazid. conclusion: it was concluded that frequency of primary drug resistance to isoniazid is quite high (20%) so its reasons need to be identified.