Prescription digital therapeutics (PDTs) are FDA-authorized, clinically validated software applications that deliver behavioral and cognitive interventions through digital platforms. While these therapeutics are prescribed and regulated like drugs, they lack an established pharmacologic framework to define how digital content is delivered, processed, and translated into clinical benefit. In this editorial, we draw on rich experience in drug and PDT development to introduce the emerging discipline of digital pharmacometrics: the application of pharmacokinetics (PK) and pharmacodynamics (PD) principles to software-based medicine. We redefine classical concepts such as dose, exposure, and the absorption, distribution, metabolism, and excretion (ADME) framework for the context of digital therapeutics and identify Digital Working Alliance (DWA) formation as a critical modulator of therapeutic bioavailability. We also characterize digital PD through the development of dose-exposure-response curves that capture behavioral, biometric, and clinical outcomes, enabling closed-loop, adaptive therapeutic systems. This digital PK/PD model supports better trial design, labeling clarity, regulatory oversight, clinical guidance, and reimbursement models. By formally codifying how PDTs interact with patients and produce effects, digital pharmacometrics provides the scientific foundation necessary to scale precision software medicine.