The Potential Role of Therapeutic Drug Monitoring for Safe and Effective Anti-Infective Therapy with Manipulated Dosage Forms

Background: Therapeutic drug monitoring (TDM) is essential for ensuring safe, effective, and individualized anti-infective therapy, particularly in patients with complex clinical needs. Variability in pharmacokinetics, challenges in drug administration, and high-dose regimens can compromise adherence and increase the risk of therapeutic failure or resistance. Swallowing difficulties, a common barrier to oral therapy, often necessitate alternative administration routes or customized formulations. However, interventions such as pharmaceutical compounding or manipulation of solid dosage forms may significantly alter drug bioavailability and pharmacokinetic profiles, making TDM indispensable for guiding dose adjustments and maintaining therapeutic targets. Objectives: This review not only emphasizes the clinical relevance of TDM but also addresses practical strategies that enable therapy when standard formulations are unsuitable or unavailable, while minimizing risks that could compromise treatment efficacy and safety. Special focus is given to anti-infective agents, such as antibiotics, antivirals, and antifungals, illustrating how TDM, combined with tailored pharmaceutical approaches, supports precision dosing and informed decision-making. Conclusions: Through clinical examples and pharmacokinetic considerations, we demonstrated that TDM is a cornerstone of personalized medicine, improving outcomes, and reducing adverse effects in anti-infective treatment.