Device for controlling the drug delivery

Device for influencing the rate of drug delivery to a patient (2) to produce a desired effect with body a drug-metering unit (10) for drug delivery, a patient model (11), which is calculated in consideration of past values ​​of the active substance supply a current value of the concentration of active compound (12) in the body of the patient (2), an active control means (8) for the drug supply which delivers a manipulated variable for the metering unit (10) in dependence on the calculated current value of the concentration of active ingredient (12) and a guide variable (7) a body effect calculation part (4), which forms a function of the difference between a target value (6) for the body effect and a measured body effect, the reference variable (7) for the active control means (8), a safety device (15) with a further patient model (16), which on the basis of past and / or current values ​​of the drug delivery future drug concentration (17) extrapolated, wherein a comparison of the extrapolated drug concentration in the safety device (15) (17) with a predetermined limit (14) performed for the maximum drug concentration and when limits are exceeded over a signal line (18), a switch (19) is actuated, shuts off the metering unit (10).