A medication dispensing apparatus having a manually operable plunger axially shiftable relative to the apparatus housing. The plunger is pullable relative to the housing in a proximal direction to cock the apparatus, and when the plunger is then manually pushed back toward the housing, a piston within a medicine container of the apparatus is shifted to force medication from a needle assembly at the distal end of the apparatus. The medication dispensing apparatus also includes a priming mechanism which is operated by rotating an externally accessible driver portion to prime the apparatus for use, which priming can be performed whether or not the apparatus is in a cocked state.