The present invention relates to a drive mechanism for a drug delivery device, comprising: a piston rod to operably engage with a piston of a cartridge to displace the piston in a distal direction during a dose dispensing action, at least one actuation member mechanically coupled with the piston rod to induce a distally directed displacement of the piston rod when actuated by a user, a control to ascertain at least one predefined condition of use, and at least one interlock member coupled with the control to mechanically obstruct displacement of the piston rod if the condition of use is not fulfilled.
