Abstract: A system for optimizing a patient s basal insulin dosage regimen over time adapted to determine from blood glucose values whether and by how much to vary a patient s present recommended amount of the insulin containing drug in order to maintain the patient s future blood glucose level measurements within a predefined range and wherein a given blood glucose value is disregarded if no patient actuated operation being indicative of the administration of a dose of an insulin containing drug has been detected in a pre defined amount of time prior to the determination of the given blood glucose value.