A device for monitoring drug use from a drug dispenser in the form of a dispenser cap, especially an inhaler, comprising a sensor for measuring drug release from the dispenser. As a drug release measurement sensor (2) a piezoelectric transducer (2) is used, while a piezoelectric transducer (2) is connected to a microprocessor. The cap includes the activator (1) of the drug release measurement sensor (2) associated movably connected with the piezoelectric transducer (2), wherein the piezoelectric transducer (2) is located in the cap in such a way that, with the help of the activator (1) of the drug release measurement sensor (2), after using the drug dispenser, the force pressure on the cap as a kinetic force is transmitted from the activator (1) of the drug release measurement sensor (2) directly to the piezoelectric transducer (2), which measures the transferred kinetic force.