What is a metered-dose inhaler?

Using a metered-dose inhaler (MDI) is the most common, quickest and easiest way to take asthma medicine. The MDI, often simply called an inhaler, is a small, pressurized can that contains aerosol medicine to be inhaled. Many asthma medications are taken with an inhaler. MDIs are also used by people who suffer other respiratory ailments such as emphysema, chronic lung disease and bronchitis.

There are five parts to an inhaler: your medication, the propellant, the canister, the metering valve and the mouthpiece. Each time you use the inhaler, a precise measured, or "metered," amount of medicine goes directly to your lungs. Inhalers can be used by all asthma patients age 5 and older, according to the American Medical Association.

Through inhalation, it takes only five to 15 minutes for short-acting bronchodilators (quick-relief medicine) to have an effect, compared to oral asthma medicines, which can take one to three hours. With an inhaler, there are also fewer medication side effects because the medicine goes right to the lungs and not to other parts of the body. A holding chamber (or spacer device) attached to the inhaler can help make taking the medication easier, for adults and children.

What is a spacer?

Spacers are tubes attached to the inhaler that act as a reservoir or holding chamber. They serve to hold the medication that is sprayed by the inhaler. This makes it easier to use your inhaler and helps ensure you get more of the medication into your lungs instead of just into your mouth or the air. With proper use, a spacer can make an inhaler 20 percent more effective in delivering medicine.

Spacers can be especially helpful to adults and children who find a regular inhaler hard to use. People who use corticosteroid inhalers should use a spacer to prevent getting the medicine in their mouth, which can cause an oral yeast infection.

How to use an MDI

It is important to use a MDI the correct way to get the needed amount of medication into your lungs. First, ask your doctor or nurse to show you how to use the inhaler. Then let them watch your technique to make sure you are doing it correctly.

Steps for using your inhaler:

1. Take off the mouthpiece cover on the inhaler, and hold the inhaler upright. Look inside to make sure it is clear of foreign matter.



2. Insert the inhaler into the spacer, if you have one.



3. Shake the inhaler for five to 10 seconds (about three to five times).



4. Hold your inhaler upright with the mouthpiece end facing down.



5. Stand or sit upright.



6. Tilt your head back slightly and breathe out.



7. Use the inhaler in any one of the following ways: (A and B are the best ways, but C is okay if you are having trouble with A or B.)

A.
Open mouth wide, with inhaler 1 to 2 inches away (about the width of two fingers).
B.
Use a spacer/holding chamber and insert into your mouth.
C.
Put the inhaler in your mouth (do not use this method with steroids). Be careful not to block the inhaler with your tongue.

8. Press down on the inhaler firmly to release the medication as you start to breathe in.



9. Breathe in slowly and completely for three to five seconds- count 1 one thousand, 2 one thousand, 3 one thousand.



10. Hold your breath for 10 seconds if possible to allow the medication to go deeply into your lungs.



11. Exhale slowly through your mouth.



12. Repeat puffs as prescribed. Wait one minute between puffs to permit the inhaler to reload with medication, and shake before using again.



13. Replace the cap on your inhaler/spacer.



14. The inhaler and spacer should be cleaned often to prevent buildup (see below).



15. Discard the canister after you have used the number of puffs (inhalations) indicated on the label.



16. Store your inhaler in a clean, sealed plastic bag.

Special instructions for inhaled corticosteroids

When taking inhaled corticosteroids, you should follow these additional instructions:

• If you are experiencing asthma symptoms, use your inhaled bronchodilator first and wait at least one to two minutes before using your inhaled corticosteroids. This helps open up the airways to allow the medication to be delivered deep into the lungs.



• Always use a spacer because this improves medication delivery to the lungs and also reduces the risk of mouth infections (yeast).



• Rinse your mouth and throat after you have finished to reduce dry mouth and hoarseness.

Common problems that affect medication dosage

If the inhaler is stored in a valve-down position for a few hours, there may be less medicine available in the first puff, even if you shake the inhaler beforehand. To avoid this problem, store your inhaler with the valve up. If the canister was stored in a valve-down position for more than four hours, don't count the first puff.

Hand-breathing coordination is difficult. If you are finding that your medications are not as effective as you may wish, you should consider using a spacer.

To improve how well your inhaler works make sure to:

• Shake the inhaler several times before every puff.



• Exhale as much air as you can push out before pressing your inhaler.



• Breathe in through your mouth, not through your nose.

How to clean your inhaler and spacer

Clean the mouthpiece and cap at least once a week by rinsing in warm water. Make sure to shake off any excess water, and let them air-dry overnight. When dry, store in a clean, sealed plastic bag to keep out dust and debris.

When does an inhaler need to be replaced?

It is important that you understand how long your inhaler will last, as it is not always easy to notice when you are running low on medication. Your inhaler is made to deliver the prescribed amount of medication until it is empty. You can calculate how long an inhaler will last using the following method:

1. Check the inhaler box to see how many "metered inhalations" or puffs it contains.



2. Next, figure out how many puffs you will take per day (eg, 2 puffs, 4 times a day = 8 puffs a day).



3. Divide this number into the number of puffs contained in the canister. That will tell you how many days the inhaler canister will last. Make sure to count forward and mark the day on your calendar that the inhaler will need to be replaced to make sure you refill your prescription beforehand.
   

   Example:
   Inhaler canister contains 200 puffs.
   You take 2 puffs, 4 times a day (2 x 4) = 8 puffs a day.
   200 divided by 8 = 25. The inhaler canister will last 25 days. In this example you would need to make sure you have a replacement canister on hand 25 days from the day you first receive the inhaler.

The flotation method for determining the contents of the canisters is questionably accurate. Recommendations from the National Asthma Education and Prevention Program suggest that the only reliable method for determining the number of doses remaining in a canister is to subtract the number of doses from the number available. Studies on flotation method are conflicting. Your spacer may need to be replaced periodically, depending on the type. Ask your doctor about replacing your spacer.