An aerosolizing device (10, 900), comprising: a housing (12, 902) sized and shaped to be held in a hand of a user; a disposable aerosolizing element (16, 130, 150, 180, 200, 250, 800, 906) disposed in the housing (12, 902) and capable of expelling aerosolized agent, the aerosolizing element (16, 130, 150, 180, 200, 250, 800, 906) comprising a body (78, 152, 182, 202, 252, 802), a front portion (80, 154, 184, 204, 254, 804), a rear portion (82, 156, 186, 206, 256, 806), a chamber (84, 158, 188, 208, 258, 808) cooperatively formed between the front portion (80, 154, 184, 204, 254, 804) and the rear portion (82, 156, 186, 206, 256, 806), agent releasing orifices (110, 138, 818) defined in the front portion (80, 154, 184, 204, 254, 804) and in communication with the chamber (84, 158, 188, 208, 258, 808), a movable portion defined in the rear portion (82, 156, 186, 206, 256, 806) and positioned in the body opposite the agent releasing orifices (110, 138, 818), and an integral reservoir (86, 160, 190, 210, 260, 810) spaced from and above the chamber at an upper end portion of the aerosolizing element in fluidic communication with an inlet of the chamber; an actuator disposed in the housing and positioned to exert vibratory oscillations on the movable portion of the disposable aerosolizing element to aerosolize agent in the chamber (84, 158, 188, 208, 258, 808) of the aerosolizing element wherein the aerosolizing element is thereby arranged to prevent agent from contacting the actuator; and wherein the disposable aerosolizing element is removable from the housing for installation and disposal; a patient interface (30, 350, 400, 450, 500, 550, 600, 650, 700, 750, 936) coupled to the housing and shaped to deliver aerosolized agent expelled from the disposable aerosolizing element to a patient; wherein the actuator comprises a first electrode, a second electrode, a piezoelectric element between the first and second electrodes (48a, 48b), and a motion transmitting member secured to the first electrode and having an end portion coupled to the movable portion of the aerosolizing element (16, 130, 150, 180, 200, 250, 800, 906), such that an oscillating electric current applied to the first and second electrodes (48a, 48b) induces vibratory motion of the piezoelectric element, which in turn induces vibratory motion of the motion transmitting member, which transmits vibratory motion to the movable portion such that the movable portion alternately moves toward the orifices (110, 138, 818) to increase pressure in the chamber and cause agent in the chamber (84, 158, 188, 208, 258, 808) to be expelled as aerosol droplets through the orifices and away from the orifices to decrease pressure in the chamber to draw agent from the reservoir through the fluid inlet and into the region of the chamber behind the orifices. a housing (12, 902) sized and shaped to be held in a hand of a user; a disposable aerosolizing element (16, 130, 150, 180, 200, 250, 800, 906) disposed in the housing (12, 902) and capable of expelling aerosolized agent, the aerosolizing element (16, 130, 150, 180, 200, 250, 800, 906) comprising a body (78, 152, 182, 202, 252, 802), a front portion (80, 154, 184, 204, 254, 804), a rear portion (82, 156, 186, 206, 256, 806), a chamber (84, 158, 188, 208, 258, 808) cooperatively formed between the front portion (80, 154, 184, 204, 254, 804) and the rear portion (82, 156, 186, 206, 256, 806), agent releasing orifices (110, 138, 818) defined in the front portion (80, 154, 184, 204, 254, 804) and in communication with the chamber (84, 158, 188, 208, 258, 808), a movable portion defined in the rear portion (82, 156, 186, 206, 256, 806) and positioned in the body opposite the agent releasing orifices (110, 138, 818), and an integral reservoir (86, 160, 190, 210, 260, 810) spaced from and above the chamber at an upper end portion of the aerosolizing element in fluidic communication with an inlet of the chamber; an actuator disposed in the housing and positioned to exert vibratory oscillations on the movable portion of the disposable aerosolizing element to aerosolize agent in the chamber (84, 158, 188, 208, 258, 808) of the aerosolizing element wherein the aerosolizing element is thereby arranged to prevent agent from contacting the actuator; and wherein the disposable aerosolizing element is removable from the housing for installation and disposal; a patient interface (30, 350, 400, 450, 500, 550, 600, 650, 700, 750, 936) coupled to the housing and shaped to deliver aerosolized agent expelled from the disposable aerosolizing element to a patient; wherein the actuator comprises a first electrode, a second electrode, a piezoelectric element between the first and second electrodes (48a, 48b), and a motion transmitting member secured to the first electrode and having an end portion coupled to the movable portion of the aerosolizing element (16, 130, 150, 180, 200, 250, 800, 906), such that an oscillating electric current applied to the first and second electrodes (48a, 48b) induces vibratory motion of the piezoelectric element, which in turn induces vibratory motion of the motion transmitting member, which transmits vibratory motion to the movable portion such that the movable portion alternately moves toward the orifices (110, 138, 818) to increase pressure in the chamber and cause agent in the chamber (84, 158, 188, 208, 258, 808) to be expelled as aerosol droplets through the orifices and away from the orifices to decrease pressure in the chamber to draw agent from the reservoir through the fluid inlet and into the region of the chamber behind the orifices.