A device including a body with a mouthpiece, a fluid reservoir mounted to slide relative to the body, a valve, a blocking element movable and/or deformable between a blocking position in which the metering valve cannot be actuated, and an actuation position in which the metering valve can be actuated; a trigger element movable and/or deformable between a locking position and a release position; and an inhalation-controlled trigger system. The blocking element including a projection that, in the locking position, co-operates with a shoulder of the trigger element to define a latch that prevents the blocking element from moving and/or deforming. The blocking element includes a lateral projection that, in the locking position of the trigger element, co-operates with a bearing surface of the trigger element to form, in the locking position of the trigger element, a second contact point between the blocking element and said trigger element.