An accessory device for delivering medications from attached press-and-breathe metered-dose inhalers (MDIs), including those medications containing hydrofluoroalkane propellants. The device includes a collapsible flexible bag to which is attached a bidirectional mouthpiece and an adaptor that receives the MDI. The mouthpiece contains a reed that functions as an audible signal. The adaptor positions the MDI at an angle to direct the aerosol spray toward the center of the bag. When triggered, the MDI discharges the aerosolized medication into the center of the bag, which medication may then be inhaled by the user through the mouthpiece. The user's inhalation causes the bag to collapse. The reed emits an audible sound if the user inhales above a pre-determined flow rate. A cap seals a gap between the adaptor and an attached canister, making the device in combination with the MDI into a closed-bag system.
