A device configured to administer a medication, the device comprising: a lower housing that includes a housing latch; a syringe supported by the lower housing and being configured to retain a medication, the syringe having a needle configured to be inserted into tissue; a needle guard that is movable relative to the lower housing along a first direction from a first position to a second position so as to expose the needle, and subsequently from the second position to a final position whereby the needle is encapsulated; an upper housing supported relative to the lower housing, the upper housing configured to receive a manual force and move with respect to the lower housing along a second direction opposite the first direction from a pre-use position to a dispensed position in response to the manual force; and a plunger rod carried by the upper housing and movable with the upper housing so as to advance relative to the syringe when the upper housing is moved along the second direction, wherein advancement of the plunger rod relative to the syringe causes the syringe to deliver the medication out the needle, the needle guard includes a needle guard latch, the needle guard latch being configured to mate with the housing latch when the needle guard moves to the final position such that the housing latch locks the needle guard in the final position, characterised in that: the housing latch releasably interferes with the upper housing when the upper housing is in the pre-use position so as to prevent the upper housing from moving toward the dispensed position, and the movement of the needle guard toward the second position, causes the interference to be removed, thereby allowing the upper housing to move from the pre-use position to the dispensed position. a lower housing that includes a housing latch; a syringe supported by the lower housing and being configured to retain a medication, the syringe having a needle configured to be inserted into tissue; a needle guard that is movable relative to the lower housing along a first direction from a first position to a second position so as to expose the needle, and subsequently from the second position to a final position whereby the needle is encapsulated; an upper housing supported relative to the lower housing, the upper housing configured to receive a manual force and move with respect to the lower housing along a second direction opposite the first direction from a pre-use position to a dispensed position in response to the manual force; and a plunger rod carried by the upper housing and movable with the upper housing so as to advance relative to the syringe when the upper housing is moved along the second direction, wherein advancement of the plunger rod relative to the syringe causes the syringe to deliver the medication out the needle, the needle guard includes a needle guard latch, the needle guard latch being configured to mate with the housing latch when the needle guard moves to the final position such that the housing latch locks the needle guard in the final position, characterised in that: the housing latch releasably interferes with the upper housing when the upper housing is in the pre-use position so as to prevent the upper housing from moving toward the dispensed position, and the movement of the needle guard toward the second position, causes the interference to be removed, thereby allowing the upper housing to move from the pre-use position to the dispensed position.