Pharmacokinetics of Ethionamide and Ethionamide Sulfoxide in Patients Established on Treatment for Tuberculosis.

Inclusion Criteria: * Provide written, informed consent prior to all trial-related procedures. * Male or female, aged between 18 and 65 years, inclusive. * Receiving Eto as a component of a treatment regimen for tuberculosis for at least one month at the time of enrolment. * Ability and willingness of participant or legally authorized representative to provide informed consent. Exclusion Criteria: * Evidence of clinically significant conditions or findings, other than TB, that might compromise safety of the participant or the interpretation of trial endpoints, per discretion of the Investigator. * Receiving prohibited concomitant medications (see Prior and Concomitant Medications) * Evidence of illicit substance use (cannabis, methamphetamines, opiates) * Pregnant or breastfeeding or planning to become pregnant during the study period. * Laboratory values: participants with the following laboratory values at screening * creatinine \>1.5 times upper limit of normal \[ULN\]; * haemoglobin \<8.5 g/dL; * Alanine aminotransferase (ALT) ≥2.0 x ULN;