What is the function of a metered dose inhaler (MDI)?

A metered dose inhaler (MDI) is designed to deliver a specific, measured dose of medication to the lungs with each spray or puff. This precision allows for effective management of respiratory conditions, such as asthma or chronic obstructive pulmonary disease (COPD), by ensuring that patients receive the correct dose at the right time, which optimizes the therapeutic effect while minimizing potential side effects.

The mechanism of an MDI typically involves a pressurized canister that releases a predetermined amount of medication. When the inhaler is actuated, it releases the medication in a fine mist, which makes it easier for the patient to inhale deeply into the lungs, where it can exert its action effectively. This metering is crucial as it ensures consistency in dosing which is vital for achieving desired clinical outcomes in managing respiratory diseases.

Other options describe functions that are not accurate for an MDI. For instance, it does not provide continuous medication throughout the day; rather, it is intended for on-demand or scheduled use. While some MDIs may deliver steroid medications, they are not limited to this class of drugs, and they are certainly not a form of oral medication, as they are specifically designed for inhalation.