A dual-chambered drug delivery device, comprising a cartridge having a first chamber for storing a medicament, a second chamber in fluid communication with said first chamber, a dose setting member for setting a medicament dose to be injected at an injection site, a piston disposed in said second chamber, an upward stroke of said piston drawing a portion of the medicament dose into said second chamber and a downward stroke of said piston expelling the portion of the medicament dose, a needle communicating with said second chamber for sequentially injecting portions of the medicament dose into the injection site, a drive screw movably connected to said dose setting member such that rotation of said dose setting member moves said drive screw upwardly, and a rack movably connected to said drive screw such that downward movement of said drive screw during the medicament dose injection rotates said rack.