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Metered Dose Inhaler

        Health | Asthma

The instructions on this page are for general information only. Always follow the directions that come with the specific inhaler you use. Your doctor should teach you how to use the inhaler correctly.

How to use a metered-dose inhaler for asthma:

  1. Remove cap and hold inhaler upright.
  2. Shake the inhaler for 5 to 10 seconds.
  3. Hold your inhaler upright with the mouthpiece at the bottom.
  4. Stand or sit upright.
  5. Tilt your head back slightly and breathe out.
  6. Open your mouth and place inhaler 1 to 2 inches away.
  7. Alternatively, you can use a spacer. See instructions below on how to use a spacer with your asthma inhaler.
  8. Be careful not to block the inhaler with your tongue.
  9. Press down once on the canister to release the medicine as you start to breathe in slowly.
  10. Breathe in slowly (for 3 to 5 seconds).
  11. Hold your breath for 10 seconds to allow the medicine to get deeply into your lungs.
  12. Exhale slowly through your mouth.
  13. Repeat puffs as directed; wait 1 minute between puffs.
  14. Replace the cap on your MDI.
  15. Store in a clean, sealed plastic bag.

How to maintain a metered dose inhaler:

Clean the mouthpiece at least once a week. Rinse in warm water and air-dry on a paper towel.


Spacers are tubes attached to the metered-dose inhaler (MDI). Spacers actually hold the medicine that is sprayed by the inhaler. This makes it easier to use your MDI and helps to get more of the medicine into your lungs instead of into your mouth or the air. Spacers can be especially helpful to adults and children who find a regular inhaler hard to use. To prevent a yeast infection, people who are currently using corticosteroid inhalers can also use a spacer to help avoid getting the medicine in their mouth.

How to use spacers:

  1. Shake the MDI canister well.
  2. Attach the spacer to the inhaler.
  3. Place the mouthpiece to your lips according to the instructions on the unit. Or, if using a mask attachment, place it over nose and mouth.
  4. Press the canister firmly to release a dose of the medicine.
  5. Breathe in deeply and slowly for 5 seconds.
  6. Hold your breath for about 10 seconds to allow the medicine to get deeply into your lungs.
  7. Exhale slowly through your nose or mouth.
  8. Wait 1 minute between puffs; repeat puffs as directed.
  9. Replace the cap on your spacer/inhaler.
  10. Clean the spacer/inhaler at least once a week; soak it in warm soapy water.
  11. Rinse well, allowing it to air-dry on a paper towel.
  12. Store in a clean, sealed plastic bag.

Your spacer may need to be replaced periodically, depending on the type. Ask your doctor about replacing your spacer.

Written by Karen Serrano, MD

Emergency Medicine resident at the University of Wisconsin-Madison.

Reviewed by Lisa V. Suffian, MD

Instructor of Clinical Pediatrics in the Division of Allergy and Pulmonary Medicine at Saint Louis Children's Hospital, Washington University School of Medicine

Assistant Clinical Professor in the Department of Pediatrics at Cardinal Glennon Children's Hospital, Saint Louis University

Board certified in Allergy and Immunology

Last updated June 2008