Asthma inhalers dispense airway-relaxing albuterol during asthma attacks. For a very long time, the makers used chemicals called chlorofluorocarbons, or CFCs to propel the drug into the lungs. Inhalers containing CFC are being phased out because these chemicals have been found to damage the Earth's protective ozone layer.

As of Dec. 31, CFC-containing asthma inhalers are no longer be made or sold in the U.S. and are being substituted by the inhalers containing ozone-friendly chemicals hydrofluoroalkanes or HFAs.

Old-fashioned inhalers will quit selling at year's end and the government is urging patients not to wait until the last minute and talk to their doctors about switching to newer alternatives.

The FDA reported that HFA inhalers will taste and feel different. The spray will feel softer and will have to be primed and cleaned in a specific way to prevent clogs. They will also cost more.

CFC-free options include GlaxoSmithKline's Ventolin HFA, Schering Plough's Proventil HFA and Ivax Corp.'s Proair HFA, all containing albuterol and Sepracor's Xopenex HFA containing levalbuterol, a similar medication.

The sole remaining maker of CFC inhalers is Armstrong Pharmaceuticals that is expected to stop production even before the deadline, FDA reported although their representatives could not immediately be reached for comment.