Therapeutic Drug Monitoring for Linezolid in the Treatment of Rifampin-resistant Tuberculosis

This study is using drug-level monitoring (called therapeutic drug monitoring) to help personalize the dose of linezolid — an antibiotic used to treat drug-resistant tuberculosis (TB), including rifampicin-resistant TB (RR-TB) and multi-drug resistant TB (MDR-TB). Linezolid can be effective but also has side effects at certain doses. **You may be eligible if...** - You are over 18 years old - You have confirmed rifampicin-resistant tuberculosis (by lab testing) - You started a TB treatment regimen containing linezolid no more than 14 days before enrollment - Your HIV status is known (both HIV-positive and HIV-negative patients can join; if unknown, testing must be done) **You may NOT be eligible if...** - You have a serious unstable medical condition that would interfere with study participation - You are pregnant at the time of screening - You are taking less than 600 mg of linezolid daily Talk to your doctor to see if this trial is right for you.