FRIDAY, May 30 (HealthDay News) -- Asthma inhalers that contain the drug albuterol to relax the airways also contain chemicals that harm the ozone layer. And these inhalers won't be available after this year, so U.S. health officials are urging patients to switch to alternative inhalers now.

Chlorofluorocarbons, or CFCs, are widely used to propel inhaled drugs into the lungs. However, products containing CFCs are being phased out, because the chemicals damage the Earth's protective ozone layer. CFC inhalers are being replaced by inhalers powered by HFAs, or hydrofluoroalkanes, which are ozone-friendly.

The change to HFA-powered inhalers has been in the works for several years, but the FDA issued an advisory on Friday, urging patients still using CFC inhalers to switch now. Inhalers containing CFCs will not be available after Dec. 31.

FDA officials said people with respiratory problems, such as asthma and chronic obstructive pulmonary disease, may need some time to acclimate to HFA-based inhalers.

"There are 52 million prescriptions written for albuterol inhalers each year in the United States," Dr. Badrul Chowdhury, director of the U.S. Food and Drug Administration's Division of Pulmonary and Allergy Products, said during a teleconference. Albuterol is used to treat shortness of breath in people with asthma and chronic obstructive pulmonary disease, he noted.

Chowdhury said that approximately 65 percent of inhaler users have already switched to HFA inhalers.

"These new handlers may taste and feel different than the current CFC inhalers," he said. "In addition, HFA inhalers may feel softer than CFC inhalers."

Also, patients using HFA inhalers will have to prime and clean them to prevent the buildup of albuterol in the inhalers' nozzle. This buildup could block the medicine from reaching the lungs, Chowdhury said.

Each HFA inhaler has a different priming mechanism and cleaning and drying instructions. So, users should carefully read the instructions before using the inhaler. And HFA inhalers may cost more, because there's no generic HFA inhaler available yet, Chowdhury said.

Three HFA-propelled albuterol inhalers have been approved by the FDA: Proair HFA Inhalation Aerosol; Proventil HFA Inhalation Aerosol; and Ventolin HFA Inhalation Aerosol. Also, an HFA-propelled inhaler containing levalbuterol, a medicine similar to albuterol, is available as Xopenex HFA Inhalation Aerosol, the agency said.

Dr. Ira Finegold, chief of the Division of Allergy and Clinical Immunology at St. Luke's-Roosevelt Hospital Center in New York City, doesn't see much difference in the effectiveness of the two types of inhalers. "The end result -- if you need it, does it open up your lungs? Yes, it does," he said.

However, the changeover will involve some patient education, he said. "The old medication, CFC albuterol, was really a very nice product, because the propellant got in your body and came out of your body -- it wasn't absorbed. And remarkably, it is a cleaning agent, so the device was self-cleaning."

The new HFA propellant is safe in the body but can clog the inhaler, Feingold said. "So, after use, these inhalers need to be rinsed out or they are not going to work correctly," he said.

"In addition," Feingold added, "each of the four new inhalers on the market is different in the number of times you have to prime it. There is also a little difference in feel and taste."

The discontinuation of CFC-propelled inhalers is the result of the U.S. Clean Air Act and an international treaty known as the Montreal Protocol on Substances That Deplete the Ozone Layer.

Under provisions of this treaty, the United States agreed to stop the production and importation of substances that damage the ozone layer, including CFCs, according to the FDA.

More information

For more on inhalers, visit the U.S. Food and Drug Administration.