From Vincent Iannelli, M.D.,
Your Guide to Pediatrics.
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About.com Health's Disease and Condition content is reviewed by Kate Grossman, MD

Definition:

An MDI (metered dose inhaler) is a pressured canister that contains a child's asthma medicine, including albuterol (Proventil HFA, Ventolin HFA, ProAir HFA), levalbuterol (Xopenex HFA), Flovent HFA (fluticasone), Advair HFA (fluticasone and salmeterol), and Symbicort (budesonide and formoterol).

To use an MDI, a child simply presses down on the inhaler and breathes in at the same time, which allows the asthma medication to get to their lungs. Without good timing, the medicine will just end up in their mouth though.

Because using an MDI can be tricky, it is recommended that younger children under age four years old use a spacer with a mask with their MDI. Older children can use a spacer with their MDI until they learn to use the MDI by itself, when they are five to six years old.

The MaxAir Autohaler (pirbuterol) is a breath-activated MDI. Unlike a traditional inhaler, with the MaxAir Autohaler, a child simply breathes in when they are ready and that activates the inhaler and releases the medication. This removes the need for the timing required with other inhalers, but younger children still have a hard time coordinating a deep breath with this inhaler, so it is mainly for older children.

Pronunciation: M.D.I.

Also Known As: Metered Dose Inhaler

Examples: A child should usually have one MDI at home and one at school, in case he has asthma symptoms and needs his inhaler during recess or PE.