Jan‐Willem C. Alffenaar

There are currently a number of licensed azole antifungal drugs; however; only 4 (namely, fluconazole, itraconazole, posaconazole, and voriconazole) are used frequently in a clinical setting for prophylaxis or treatment of systemic fungal infections. In this article, we review the pharmacokinetic interactions of these azole antifungal drugs with other coadministered agents. We describe these (2-way) interactions and the extent to which metabolic pathways and/or other supposed mechanisms are involved in these interactions. This article provides an overview of all published drug-drug interactions in humans (either healthy volunteers or patients), and on the basis of these findings, we have developed recommendations for managing the specific interactions.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) pandemic has attracted interest because of its global rapid spread, clinical severity, high mortality rate and capacity to overwhelm healthcare systems [1, 2]. SARS-CoV-2 transmission occurs mainly through droplets, although surface contamination contributes and debate continues on aerosol transmission [3–5]. Diagnostic, treatment and outcome details of 49 COVID-19 patients with concurrent or previous tuberculosis from 8 countries show varied clinical profiles <https://bit.ly/369ZGGu> The article is part of the scientific activities of the Global Tuberculosis Network (GTN); GREPI (Groupe de Recherche et d'Enseignement en Pneumo-Infectiologie), a working group from SPLF (Société de Pneumologie de Langue Française); SEPAR (Sociedad Española de Neumología and Cirugía Torácica); Moscow Society of Phtisiology and of the WHO Collaborating Centre for Tuberculosis and Lung Diseases, Tradate, ITA-80, 2017-2020- GBM/RC/LDA). Delia Goletti is a professor of Pathology at Unicamillus University in Rome, Italy. The authors wish to thank Enrico Girardi (National Institute for Infectious Diseases, L. Spallanzani, IRCCS, Rome, Italy) for the useful comments on the manuscript.

Dried blood spot (DBS) analysis has been introduced more and more into clinical practice to facilitate Therapeutic Drug Monitoring (TDM). To assure the quality of bioanalytical methods, the design, development and validation needs to fit the intended use. Current validation requirements, described in guidelines for traditional matrices (blood, plasma, serum), do not cover all necessary aspects of method development, analytical- and clinical validation of DBS assays for TDM. Therefore, this guideline provides parameters required for the validation of quantitative determination of small molecule drugs in DBS using chromatographic methods, and to provide advice on how these can be assessed. In addition, guidance is given on the application of validated methods in a routine context. First, considerations for the method development stage are described covering sample collection procedure, type of filter paper and punch size, sample volume, drying and storage, internal standard incorporation, type of blood used, sample preparation and prevalidation. Second, common parameters regarding analytical validation are described in context of DBS analysis with the addition of DBS-specific parameters, such as volume-, volcano- and hematocrit effects. Third, clinical validation studies are described, including number of clinical samples and patients, comparison of DBS with venous blood, statistical methods and interpretation, spot quality, sampling procedure, duplicates, outliers, automated analysis methods and quality control programs. Lastly, cross-validation is discussed, covering changes made to existing sampling- and analysis methods. This guideline of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology on the development, validation and evaluation of DBS-based methods for the purpose of TDM aims to contribute to high-quality micro sampling methods used in clinical practice.