Abstract: An inhalation device for dispensing a medicament from a metered dosage cartridge that includes a hand-held housing having a mouthpiece and a passageway for ambient air, a triggering mechanism mounted in the housing, a biasing device for moving the cartridge to operative relationship with the passageway upon activation by the triggering mechanism, and a battery-powered circuit in the housing including a switch associated with the passageway and a solenoid operated mechanism secured to the housing for activating the trigger mechanism, with the switch acting to close the circuit and so activate the solenoid so as to activate the trigger mechanism and the biasing device so that the cartridge positions an activated outlet pin into the passageway. The switch is activated by the pressure of the passage of air drawn through the passageway by the inhaling action of the patient.