The goal of this clinical trial is to assess the efficacy(effectiveness) of doxycycline, a potent inhibitor of matrix metalloproteinase (lung collagenase) activity in prevention of Tuberculosis associated lung fibrosis and associated lung function decline among patients with drug sensitive advanced TB. The main question\[s\] it aims to answer are: * Does doxycycline have a significant anti-fibrosis role when given as adjuvant therapy to TB patients with advanced pulmonary TB in a double blind randomized placebo controlled trial? * How does long term respiratory function defer between patients who received adjuvant doxycycline aimed at prevention of TB associated lung fibrosis and those who received a placebo in a double blind randomized controlled trial? Participants will be subjected to the following: * Experimental arm: Doxycycline 100 mg once daily for 12 weeks administered concurrently with standard of care anti-TBs. * Comparator arm: Placebo once daily for 12 weeks administered concurrently with standard of care anti-TBs.