metered dose inhaler
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1. an apparatus for administering vapor or volatilized medications by inhalation.
metered dose inhaler an inhaler used to deliver aerosolized medications in fixed doses to patients with respiratory disease.
metered dose inhaler (MDI)
a device designed to deliver a measured dose of an inhaled drug. It usually consists of a canister of aerosol spray, mist, or fine powder that releases a specific dose each time it is pushed against a dispensing valve. The device is intended to reduce the risk of overmedication by the patient.