Metered-dose inhalers, sometimes referred to by their acronym MDIs, made their first appearances in 1956 to safely house and dispense asthma medication. Their appearance made a difference in how asthma could be treated: Individuals with asthma could carry their medication anywhere and use it anytime.

The Changed MDI

The MDIs, which are small plastic devices that hold medicine in an aerosol container, are probably a familiar sight to those with asthma. The MDI pressurized container contains a chemical propellant, which is now being replaced. For years, the container used chlorofluorocarbons(CFCs), which are now being banned because of global concerns about their impact on the ozone layer. These inhalers will no longer be available by the end of 2008.

These are being replaced by inhalers with the same medicine but a different propellant called hydrofluoroalkanes (HFAs). The Food and Drug Administration has noted that HFA inhalers are safe and effective, and patients should not find any significant differences from their CFC inhalers.

You will need to carefully read the directions on each inhaler to see what changes may have been made to dosage capacity and shelf life. Some of the inhalers with HFA will now use counters to track how much medicine is left. For those without counters, users can determine the life of the inhaler by dividing the number of puffs listed on the medicine with the number of days the medicine is expected to be used. But, medical advisors have suggested that these users keep a backup inhaler handy — just in case they run out.

Using an MDI

On the surface, using an MDI to deliver medicine looks simple enough, but the reality is that many patients usually do not use it the right way. When your child uses his MDI incorrectly, less medicine will get into his lungs to do its work.

To assist your child with using his inhaler without a spacer (see discussion in next section), you or your child should:

• Remove cap from the inhaler and hold the container upright.

• Mix the contents in the inhaler by shaking it several times, and turn canister bottom toward ceiling (so mouthpiece is on the bottom).

• Have your child breathe out.

• Use one of two methods to prepare to inhale medicine: close mouth around inhaler mouthpiece or hold mouthpiece an inch away from the mouth.

• Press down canister and begin to breathe slowly and deeply.

• Hold his breath as he counts to ten slowly (to let the medication into the breathing tubes).

• Wait about a minute if another puff is to follow.

• Have him rinse his mouth afterward to help decrease any aftertaste or unwanted side effects.

Remember to clean the inhaler as needed. If you see powder or residue in or around the hole where the medicine sprays out, you can clean the inhaler by taking out the metal canister from the L-shaped plastic mouthpiece. Rinse the mouthpiece and cap in water, and let them air-dry overnight.