A device (1) for dispensing a substance to a patient comprising a cylindrical first container (2) containing the substance and a second container (3) containing a liquid. The device further comprises an injection device (4) and transfer mechanism (5) for transferring the liquid from the second container (3) to the first container (2) and from the first container (2) to the injection device (4). The first container (2) has a connection element (7) and a plunger (9) that can be moved between the first (6) and second ends (8). By moving the plunger (9) towards the first end (6), liquid contained therein can be dispensed via the injection device (4). The injection device (4) comprises a piercing cannula (15) and an indwelling cannula (16). In an initial position, a distal end region of the piercing cannula (15) extends coaxially in the interior of the indwelling cannula (16).
