Can you tell me something about Inhalers for Asthma: Part 2

Metered Dose Inhalers use a chemical propellant to push a measured dose of medication out of the inhaler. These small light weight devices have a pressurized canister which contains the bronchodilator medication, a mouthpiece and a metering valve that dispenses the right dose of drug. The chemical propellant in the latest metered dose inhalers is hydrofluoroalkane (HFA).

These inhalers can be activated by either squeezing the canister or inhaling- either actions results in the release of the drug. Because metered dose inhalers can be difficult to use for some individuals, one can add a spacer to the inhaler. These small plastic tubes with a chamber can make the use of an inhaler easier and comfortable. When the inhaler is squeezed, the drug is first released into the chamber which then allows the individual enough time to inhale more slowly. Research has shown that the use of a spacer allows the medication to enter the lower lungs and not just remain in the throat/mouth. Many of the current metered dose inhalers have counters that let the individual know how many doses are remaining.