Eight Drugs a Week Episode 19 – I Want to Hold Your Hand: Guiding Clinicians Through Antifungal TDM

Fungal infections remain a stubborn clinical problem: treatment options are limited, and the margin between an ineffective dose and a toxic one is often narrow. Getting antifungal exposure right for each patient is not a formality; it can be the difference between clearing an infection and losing ground to it. Therapeutic drug monitoring (TDM) offers clinicians a way to walk that line with more confidence, protecting efficacy on one side and guarding against adverse effects on the other.

In this episode, Isabel Spriet and João Telles, both deeply immersed in antifungal TDM in their respective hospitals, walk us through what it takes to guide a patient safely through azole therapy: choosing the first dose without perfect information, watching for the factors that push exposure up or down, negotiating for hospital resources to make TDM possible, and untangling drug interactions that still defy easy explanation.

In this episode we'll hear about:

• How azole TDM (especially for voriconazole) is embedded into daily practice in Leuven and São Paulo, and where turnaround times still get in the way of timely dose decisions

• The negotiation it takes to win hospital buy-in for a dedicated TDM team, built on clinical outcomes, value-based healthcare, and cost-effectiveness arguments

• Why azole monitoring means tracking liver function, inflammation, genetic polymorphisms, and ECMO-related drug sequestration alongside plasma concentrations

• Isabel's research into the flucloxacillin-voriconazole interaction, an abrupt CYP450-driven concentration drop that breaks the usual rules of enzyme induction

• Where TDM should go next: echinocandin monitoring, filter adsorption during continuous renal replacement therapy, and unexplained treatment failures with micafungin

About our guests:

• Isabel Spriet is Head of the Clinical Pharmacy Department at University Hospitals Leuven and Professor at KU Leuven.

• João Telles is an infectious disease physician at the AC Camargo Cancer Centre in São Paulo, where he leads a dedicated antimicrobial TDM team.

Eight Drugs a Week is supported by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT). The personal views of the hosts and guests do not necessarily reflect the position of the Association.