Drug delivery device including motion detection system

A computerized electro-mechanical drug delivery device configured to deliver at least one dose of two or more medicaments. The device comprises a control unit. An electro-mechanical drive unit is operably coupled to the control unit and a primary reservoir for a first medicament and a secondary reservoir for a fluid agent, e.g. a second medicament. An operator interface is in communication with the control unit. A single dispense assembly is configured for fluid communication with the primary and the secondary reservoir. Activation of the operator panel sets a first dose from the primary reservoir and based on the first dose and a therapeutic dose profile, the control unit is configured to determine a dose or range of the fluid agent. Alternatively, the control unit determines or calculates a dose or range of a third medicament. Further, a dispense interface for use with a drug delivery device is disclosed.