A system comprising a prescription-determination-module that is configured to: receive patient-model-data, wherein the patient-model-data comprises one or more dose-effect- parameters that represent how a patient is expected to react to a dose of medicament over time; apply a plurality of different dosage-parameters to the patient-model-data, in order to determine a plurality of dosage-effect-data; apply one or more selection-criteria to the plurality of dosage-effect-data in order to determine one or more of the associated dosage- parameters as selected-dosage-parameters; and provide an output-signal based on the selected-dosage-parameters.