Junjie DingNguyen Thuy Thuong ThuongToi Van PhamDorothee HeemskerkThomas PouplinChau Thi Hong TranMai Thi Hoang NguyenPhu Hoan NguyenLoc Phu PhanChau Van Vinh NguyenGuy ThwaitesJoel TarningUCLMahidol UniversityNuffield Department of Clinical MedicineWorldWide Antimalarial Resistance NetworkOxford University Clinical Research Unit2020-03-262020-03-262020-01-01Clinical Pharmacology and Therapeutics. (2020)15326535000992362-s2.0-85080975510https://repository.li.mahidol.ac.th/handle/123456789/53871© 2020 The Authors. Clinical Pharmacology & Therapeutics published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics. The most effective antituberculosis drug treatment regimen for tuberculous meningitis is uncertain. We conducted a randomized controlled trial comparing standard treatment with a regimen intensified by rifampin 15 mg/kg and levofloxacin for the first 60 days. The intensified regimen did not improve survival or any other outcome. We therefore conducted a nested pharmacokinetic/pharmacodynamic study in 237 trial participants to define exposure–response relationships that might explain the trial results and improve future therapy. Rifampin 15 mg/kg increased plasma and cerebrospinal fluid (CSF) exposures compared with 10 mg/kg: day 14 exposure increased from 48.2 hour·mg/L (range 18.2–93.8) to 82.5 hour·mg/L (range 8.7–161.0) in plasma and from 3.5 hour·mg/L (range 1.2–9.6) to 6.0 hour·mg/L (range 0.7–15.1) in CSF. However, there was no relationship between rifampin exposure and survival. In contrast, we found that isoniazid exposure was associated with survival, with low exposure predictive of death, and was linked to a fast metabolizer phenotype. Higher doses of isoniazid should be investigated, especially in fast metabolizers.Mahidol UniversityMedicinePharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1002/cpt.1783