A method and system for limiting a maximum dose that may be set in a drug delivery device. A dose setting mechanism, which is operable to be coupled to a medication cartridge, comprises a lock-out mechanism that prevents one from setting a dose greater than the medication in the cartridge. The lock-out mechanism comprises a rotatable shaft. A helical groove having a first pitch is provided along a first portion of the rotatable shaft and a second pitch provided along a second portion of the rotatable shaft. The first pitch is different from the second pitch. A third pitch may be provided on a third portion of the shaft. This third pitch is provided at the end of the second pitch and is preferably different than the second pitch. The lock-out mechanism further comprises a non-rotating member disposed on the helical groove of said shaft. During dose setting, the shaft is rotated relative to the non-rotating member while the non-rotating member traverses along the groove from a proximal end of the shaft towards a distal end of the shaft.
