Metered dose inhalers (MDIs) that contain chlorofluorocarbons (CFCs) are being phased out. Manufacturers use CFCs as propellants to move the medicine out of the inhaler so patients can breathe the medicine into their lungs.

CFCs are harmful to the environment because they decrease the protective ozone layer above the Earth.

The United States, along with most other countries, are eliminating CFCs because of an international agreement, called Montreal Protocol on Substances that Deplete the Ozone Layer.

Patients will need to talk to their health care professionals and switch to another medicine before the phase-out of their CFC inhalers is completed.

Though CFC asthma inhalers have been used to treat asthma for years, they are now banned in United States and many other parts of the world. CFC inhalers are safe for you to use, but they can deplete the earth's ozone layer -- our greatest protection from the sun's powerful rays.

Because of this, the U.S. Food & Drug Administration (FDA) passed a law requiring drug makers to repackage metered dose inhalers (MDIs) so they'll be healthier for our environment. 

The medicines in the HFA inhalers are the same as those in the CFCs.

The new inhalers have proven in rigorous FDA studies to be just as effective as the old ones.

The dose and frequency for individual medicines remains the same.

Few differences between HFA MDI and CFC MDI inhalers are as below:

• The new inhalers may taste and smell slightly different.
• Because the spray is less forceful, the HFA spray feels less cold coming out of the canister.
• The HFA inhalers must be primed more than the old CFC inhalers needed to be.
• They also need to be cleaned more often to avoid clogging.
• There's more variation among brands of HFA inhalers than there was with the CFC versions. So, finding the one that works best might require a bit of trial and error.
• They cost a lot more because there are not generic equivalents to the costly brands yet.