The search for new drugs is an extremely time-consuming and expensive endeavour. Much of that time and money go into generating predictive human pharmacokinetic profiles from preclinical efficacy and safety animal data. These pharmacokinetic profiles are used to prioritize or minimize the attrition at later stages of the drug discovery process. In the area of antiviral drug research, these pharmacokinetic profiles are equally important for the optimization, estimation of half-life, determination of effective dose, and dosing regimen, in humans. In this article we have highlighted three important aspects of these profiles. First, the impact of plasma protein binding on two primary pharmacokinetic parameters—volume of distribution and clearance. Second, interdependence of primary parameters on unbound fraction of the drug. Third, the ability to extrapolate human pharmacokinetic parameters and concentration time profiles from animal profiles.

The rapid emergence of antimicrobial resistance (AMR) has become a significant challenge in both human and veterinary medicine, largely driven by the misuse and overuse of antibiotics, including inappropriate cross-species dosage extrapolation. Empirical antimicrobial dosing can result in subtherapeutic exposure, disruption of the microbial ecosystem, and increased selective pressure, thereby accelerating the emergence and dissemination of resistant bacteria. Maintaining microecological homeostasis, particularly the stability of the commensal microbiota, is increasingly recognized as essential for limiting the development of resistance and preserving host health. Although interspecies scaling, Monte Carlo simulations, population pharmacokinetics (PK), and physiologically based PK models have been used to predict dosage regimens, their complexity and extensive data requirements restrict routine application in veterinary practice. In this context, PK/pharmacodynamic (PD) modeling provides a practical and scientifically robust framework for rational antimicrobial therapy. By integrating drug concentration–time profiles with antimicrobial effects, PK/PD-guided approaches enable species-specific dose optimization that improves therapeutic efficacy, minimizes ecological disruption, and reduces AMR selection pressure. This review highlights the application of modern PK/PD strategies in veterinary medicine as an essential tool for sustainable antimicrobial stewardship, AMR mitigation, and preservation of microbial ecosystem stability.