This episode is about the TDM of antiretroviral drugs, an area with a boom in research output in the late 90s and early 2000s, generating enough randomized controls trials for a substantial systematic Cochrane review on the topic (a rare thing for TDM research!). It’s an ever-evolving space, where drug regimens are continually refined with newer drug options with fewer adverse effects. However, we have learned a lot through concentration monitoring, and TDM continues to be very useful in optimizing treatment. As our title suggests, this is a continuing story. Our guests today are Natella Rakhmanina and Dario Cattaneo, who have been involved in the story since the beginning but from different perspectives, Natella as a paediatric infectious diseases specialist and Dario as a clinical pharmacologist. We cover the history, discuss the role that TDM has today and consider where things are headed. In this episode we hear about: •    The usefulness and limitations of using TDM to monitor adherence. •    Diverse niche patient scenarios where TDM can be very helpful, which are not at all uncommon.  •    Interesting challenges where TDM can be helpful, some that are particular to paediatric patients, and others to elderly HIV patients. •    Learnings from TDM for long-acting drugs in psychiatry, and the implications for novel depot antiretroviral formulations. •    Drug interaction attributable to antiretrovirals, and those that affect them. •    Why, despite viral monitoring, TDM for antiretrovirals can still be very useful.  •    What Paxlovid tastes like. 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.    To join IATDMCT, visit https://www.iatdmct.org/member-join    Subscribe to Eight Drugs a Week on your preferred podcast platform.    About our guests: Natella Rakhmanina is a Professor at the Department of Paediatrics, School of Medicine and Health Sciences of The George Washington University. She is also director of HIV Services of the Division of Infectious Diseases at the Children’s National Hospital in Washington. Dario Cattaneo is currently the President of the IATDMCT. He is a clinical pharmacologist at Luigi Sacco University Hospital in Milan and an Adjunct Professor at the University of Milan, Italy.