A method, a system, and a computer program for calibration of sensitivity of a subject to a drug. The subject is delivered with the drug at a delivery rate and a signal responsive to the drug is measured from the subject. When determining the sensitivity of the subject to the drug in question, a change in the delivery rate of the drug is initiated. The change in the delivery rate causes a small change in the signal responsive to the drug. The change in the measured signal caused by the drug delivery rate change is detected, and the sensitivity of the patient is determined.
