How to Use a Metered-Dose Inhaler (MDI)

Using your MDI correctly is essential for getting your full asthma medication dosage

Different metered-dose inhalers (MDIs) look the same on the outside, but each is distinctly different in operation and maintenance.

You must inhale the spray quickly enough to prevent it from landing on your tongue or inside your cheek, yet slowly enough to let it get deep into your lungs.

Metered-Dose Inhaler Step-By-Step Instructions:


  1. Remove the MDI mouthpiece cap and look at the tiny exit hole where the medication comes out of the canister. It should be free of debris or white powder. If it’s not, follow package instructions to thoroughly clean the inhaler.
  2. Shake the inhaler if necessary, to mix the powder medication with other ingredients inside go through the digestive system and bloodstream, the canister. Check your patient instruction sheet to see if your inhaler requires shaking (and how much), as a few brands (including Alvesco® and QVAR®) are blended differently and don’t need shaking.
  3. Prime the inhaler if necessary. When the MDI is new or hasn’t been used in a while, the ingredients may separate. Priming ensures the dose you inhale contains the labeled amount of medication. (Note: Priming instructions are different for each MDI brand; check your patient instruction sheet.) When using a valved holding chamber, insert the MDI mouthpiece into the end port of the chamber after priming.
  4. Stand or sit up straight and breathe out completely. Emptying your lungs as much as possible gives you room to inhale the medication slowly and deeply.
  5. Hold the inhaler upright with the mouthpiece at the bottom and the top pointing up. Position it as instructed by your physician or the medication’s patient instruction sheet. Some recommend holding the inhaler about 1-2 inches away from your open mouth; others recommend putting the MDI mouthpiece between your teeth and closing your lips tightly around it. Be sure to keep your tongue out of the way of the spray.
  6. Begin to inhale slowly, then activate the inhaler a split-second later. If you wait too long, you won’t have enough breath left to inhale the medicine deep into your small airways.
  7. Continue inhaling slowly for 3-5 seconds, until your lungs are full. You might be surprised at how long a time that is, so test yourself. Using a stopwatch device or clock with a second hand, begin to inhale and pretend to actuate your inhaler. See how long it takes you to fill your lungs. Did you run out of room in your lungs before three seconds? If so, try it again, more slowly. Practice until you’re able to get it right. Then practice again … and again.
  8. Hold your breath for 10 seconds, if possible. (You can take the inhaler out of your mouth.) When you hold your breath, you allow the tiny particles of medication to settle on the surface of your airways.
  9. Exhale slowly.
  10. Repeat steps 2 through 9 if your Asthma Action Plan says to take a second dose. (Skip step 3; your inhaler would not need to be primed again so soon.(
  11. Replace the cap on your inhaler and store it where it won’t be exposed to moisture or extreme temperature changes. Check your patient instruction sheet to see if. Your inhaler needs to be stored in an upright position. For best results, store and use the inhaler at normal room temperature – between 59 and 77 degrees F. In very cold weather, keep it close to your body, not in your car or in a backpack. In cold temperatures, warm the inhaler with your hands before using it.
  12. Clean the inhaler according to your patient instructions, usually weekly. If using water, leave time for the inhaler to air dry.
Resources from the National Heart, Lung, and Blood Institute of the NIH
How to Use a Metered-Dose Inhaler:
English Version
How to Use a Metered-Dose Inhaler:
Spanish Version

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