In this paper we introduce The Drugulator - a new method for performing dosage calculations at the administration stage of a patient's medical management. In this method users first construct a dosage's mathematical formulation from within the Drugulator's structured interface. This formulation is then evaluated by sending it to an attached computational backend that then returns any constituent calculations along with the patient's final dose. This process of Formulaic and Computationally-Aided Dosing (FCAD), and in particular, the single-interface Drugulator implementation described here, makes it practical to readily automate a wide range of dosage calculations at the point of care. This practicality also enables further automation through a progressive integration with existing medical systems. Finally, we argue that the principle underpinning the deployment of
a single interface can also be used to improve the usability of those computer provider order entry systems that include clinical decision support (CPOEcds).