A drug delivery device comprising or being adapted to receive a drug-filled cartridge, the drug delivery device comprising a geared drive arrangement, the geared drive arrangement comprising: - a stationary portion in the form of a housing (220, 510), - a drive rod in the form of a piston rod defining a reference axis and during operation being arranged to rotate and be moved axially corresponding to the reference axis, the piston rod being adapted to engage and axially displace a piston in a loaded cartridge in a distal direction to thereby expel a dose of drug from the cartridge, the piston rod comprising a second thread, - a drive member (420, 421) in engagement with the piston rod and being arranged to rotate corresponding to the reference axis, and - a nut portion comprising a propulsion thread, the nut portion during operation being arranged rotationally and axially locked relative to the stationary portion and in threaded engagement with the piston rod second thread, wherein: - the drive member (420, 421) is arranged to rotate corresponding to the reference axis during operation, the drive member being axially stationary relative to the housing during expelling of a dose of drug, - the engagement (423, 413) between the drive member and the piston rod is configured to cause the piston rod to rotate when the drive member rotates, and - the threaded engagement (431, 411) between the nut portion and the piston rod is configured to cause the drive rod to move axially, characterized in that - the piston rod comprises a first thread, - the drive member (420, 421) comprises a drive thread in threaded engagement with the piston rod first thread and is arranged to rotate corresponding to the reference axis, and - the first and the second threads (413, 411) are inclined in an opposed manner. - a stationary portion in the form of a housing (220, 510), - a drive rod in the form of a piston rod defining a reference axis and during operation being arranged to rotate and be moved axially corresponding to the reference axis, the piston rod being adapted to engage and axially displace a piston in a loaded cartridge in a distal direction to thereby expel a dose of drug from the cartridge, the piston rod comprising a second thread, - a drive member (420, 421) in engagement with the piston rod and being arranged to rotate corresponding to the reference axis, and - a nut portion comprising a propulsion thread, the nut portion during operation being arranged rotationally and axially locked relative to the stationary portion and in threaded engagement with the piston rod second thread, - the drive member (420, 421) is arranged to rotate corresponding to the reference axis during operation, the drive member being axially stationary relative to the housing during expelling of a dose of drug, - the engagement (423, 413) between the drive member and the piston rod is configured to cause the piston rod to rotate when the drive member rotates, and - the threaded engagement (431, 411) between the nut portion and the piston rod is configured to cause the drive rod to move axially, - the piston rod comprises a first thread, - the drive member (420, 421) comprises a drive thread in threaded engagement with the piston rod first thread and is arranged to rotate corresponding to the reference axis, and - the first and the second threads (413, 411) are inclined in an opposed manner.