Further detail of pharmacokinetic sampling: All subjects initiating anti-TB treatment will have venous blood samples drawn for pharmacokinetic study at 2 weeks and 12 weeks after initiation. The 2 week time point allows steady state accumulation of anti-TB drug levels, and the 12 week mark compares changes in response to treated disease, improved malabsorption or weight gain and/or initiation of antiretroviral (anti-HIV) therapy.