Metered-Dose Inhaler Defined

A metered-dose inhaler is a device used to deliver medication into your lungs.

A metered-dose inhaler has a pressurized canister of medication that fits into a mouthpiece. In most instances, a dose of medication is released into your lungs by pushing the canister into the mouthpiece. Another type releases medication automatically when you inhale. Some metered-dose inhalers have counters that track how many doses remain.

Dry powder inhalers (DPI) are breath-activated. The medication is released only when you take a deep, fast breath in through the inhaler.

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