Metered-dose inhaler

Metered-dose inhaler (MDI) is a device that delivers a specific amount of medication to the lungs, in the form of a short burst of aerosolized medicine that is usually self-administered by the patient via inhalation. It is the most commonly used delivery system for treating asthma, chronic obstructive pulmonary disease (COPD) and other respiratory diseases.

Design

The medication in a metered dose inhaler is most commonly a bronchodilator, corticosteroid or a combination of both for the treatment of asthma and COPD. Other medications less commonly used but also administered by MDI are mast cell stabilizers, such as cromoglicate or nedocromil.

Use

To use the inhaler the patient presses down on the canister while breathing in through the mouth. This releases one dose of the medicine. Spacer devices can be used with MDIs to improve drug delivery by reducing the speed and force of the medication being delivered, and by holding the medication in the chamber long enough for the patient to inhale slowly and deeply, ensuring better distribution in the lungs.

Advantages and disadvantages

MDIs are portable and convenient, making them easy to use in an emergency. They are also an effective method of drug delivery. However, they require careful timing between pressing the canister and breathing in, which can be difficult for some patients.

See also

• Asthma
• Chronic obstructive pulmonary disease
• Inhaler
• Nebulizer

References

Metered-dose inhaler Resources
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