Therapeutic drug monitoring practice in patients with active tuberculosis: assessment of opportunities

Recently updated World Health Organization (WHO) and American Thoracic Society guidelines include recommendations for therapeutic drug monitoring (TDM) during treatment for Mycobacterium tuberculosis in patients at risk of altered drug exposure or poor prognosis [1, 2]. Sub-optimal drug exposure may be associated with acquired resistance and poor treatment outcomes [3] whereas supra-therapeutic concentrations may lead to toxicity. TDM is indicated in patients at risk of altered pharmacokinetics (e.g. HIV, diabetes mellitus, gastrointestinal abnormalities, drug–drug interactions, renal impairment) and/or worsened treatment prognosis (inadequate treatment response despite adherence or on second line drugs, especially for fluoroquinolones, linezolid and aminoglycosides) [1, 2, 4]. Despite such importance, implementation of TDM is low, and guidelines do not provide specific pharmacokinetic/pharmacodynamic (PK/PD) target ranges, mainly due to the lack of available high-quality prospective studies validating these markers [5]. In light of current gaps in the evidence and rationale for future TDM studies, our study aimed to evaluate how patients could potentially benefit from TDM based on the updated guidelines [1, 2].