The purpose of this study is to evaluate the effect of gastrectomy on pharmacokinetic profile of first-line anti-tuberculosis drugs in patients with pulmonary tuberculosis (TB).

Gastrectomy is a well-known risk factor for TB. Also, there were some reports about malabsorption of anti-TB drugs in the gastrectomized patients. However, pharmacokinetics of recently used first line anti-TB drugs in the gastrectomized patients have not been well evaluated simultaneously. Therefore, the investigators aim to evaluate the effect of gastrectomy on pharmacokinetic profile of first-line anti-TB drugs in patients with pulmonary TB through this study.

Inclusion Criteria:

1. Age greater than 18 years and less than 80 years
2. pulmonary TB confirmed by microbiologic test such as AFB culture or TB PCR
3. usage of 4 first-line anti-TB drugs (Isoniazid(INH) Rifampin(RFP) Ethambutol(EMB), Pyrazinamide(PZA) = HREZ)

Exclusion Criteria:

1. patients with liver disease (bilirubin ≥ 1.5 mg/d or AST ≥ 2 x normal upper limit) or chronic renal failure (Cr ≥ 2.0 mg/d) who cannot use first-line anti-TB drugs
2. patients with AIDS or hypoalbuminemia(albumin < 3.0g/dl)that will influence pharmacokinetics of first line anti-TB drugs
3. patients using other drugs that will influence pharmacokinetics of first line anti-TB drugs during anti-TB treatment (e.g warfarin)
4. patients using anti-cancer or immunosuppressive agents that will influence the response of pulmonary TB to anti-TB drugs
5. discontinuation of first-line anti-TB drugs(HREZ)due to side effect or resistance
6. follow-up loss before completion of anti-TB treatment
7. any condition making the patients undergo gastrectomy during anti-TB treatment in case of Non-gastrectomy group

Among patients with pulmonary TB diagnosed in our hospital and treated with 4 first line anti-TB drug(isoniazid/rifampicin/ethambutol/pyrazinamide= HREZ), we recruit patients who underwent gastrectomy to Gastrectomy group. And then, we recruit age-sex matched patients who did not underwent gastrectomy to Non-gastrectomy group.(age ±3 years)