A drug delivery device to set and to dispense a dose of a medicament and comprising: - a cartridge holder to receive a cartridge filled with a medicament, - a housing to accommodate a drive mechanism, the housing being operably connectable with the cartridge holder, the drive mechanism 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 (17, 18) mechanically coupled with the piston rod to induce a distally directed displacement of the piston rod when actuated by a user, - a control integrated into the drive mechanism to ascertain at least one predefined condition of use, - at least one interlock member (30; 50; 74) coupled with the control to mechanically obstruct displacement of the piston rod if the condition of use is not fulfilled, wherein the interlock member (30; 50; 74) is adapted to releasably engage with the piston rod to impede or to obstruct a rotation or sliding motion of the piston rod in distal direction, characterized in that the piston rod is threadedly engaged with a correspondingly threaded insert portion of the housing and wherein the interlock member is arranged on the threaded insert near a central and threaded through opening thereof and comprises radially inwardly extending interlock protrusions to engage with an outer thread of the piston rod. - a cartridge holder to receive a cartridge filled with a medicament, - a housing to accommodate a drive mechanism, the housing being operably connectable with the cartridge holder, the drive mechanism 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 (17, 18) mechanically coupled with the piston rod to induce a distally directed displacement of the piston rod when actuated by a user, - a control integrated into the drive mechanism to ascertain at least one predefined condition of use, - at least one interlock member (30; 50; 74) coupled with the control to mechanically obstruct displacement of the piston rod if the condition of use is not fulfilled, wherein the interlock member (30; 50; 74) is adapted to releasably engage with the piston rod to impede or to obstruct a rotation or sliding motion of the piston rod in distal direction, characterized in that the piston rod is threadedly engaged with a correspondingly threaded insert portion of the housing and wherein the interlock member is arranged on the threaded insert near a central and threaded through opening thereof and comprises radially inwardly extending interlock protrusions to engage with an outer thread of the piston rod. - 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 (17, 18) mechanically coupled with the piston rod to induce a distally directed displacement of the piston rod when actuated by a user, - a control integrated into the drive mechanism to ascertain at least one predefined condition of use, - at least one interlock member (30; 50; 74) coupled with the control to mechanically obstruct displacement of the piston rod if the condition of use is not fulfilled, wherein the interlock member (30; 50; 74) is adapted to releasably engage with the piston rod to impede or to obstruct a rotation or sliding motion of the piston rod in distal direction, characterized in that the piston rod is threadedly engaged with a correspondingly threaded insert portion of the housing and wherein the interlock member is arranged on the threaded insert near a central and threaded through opening thereof and comprises radially inwardly extending interlock protrusions to engage with an outer thread of the piston rod.