Conducted by two university professors and a director for the Food and Drug Administration, the review examines the consequences of switching to hydrofluoroalkane, which is replacing chlorofluorocarbon, or CFC, as a key ingredient in albuterol inhalers designed to relieve asthma. The FDA has ruled that U.S. sales of CFC albuterol inhalers be prohibited after 2008.
About 52 million prescriptions are filled for albuterol each year in the United States, with most containing a generic version of CFC. But because of rising global concerns about CFC's ozone-depleting effects, "medically essential" inhalers are finally joining a list of banned products that started in 1978.
The researchers say their analyses show that inhalers with CFC and the new brands that contain hydrofluoroalkane, or HFA, are equally effective at treating asthma.
"Hopefully, by communicating with health-care professionals, we'll be able to reassure patients," said Leslie Hendeles, the University of Florida professor of pharmacy and pediatrics who spearheaded the review. He worked with Dr. Gene L. Colice, a professor of medicine at The George Washington University School of Medicine, and Dr. Robert J. Meyer, who directs the Office of Drug Evaluation II at the FDA.
Albuterol, one of the medicines that relieves asthma attacks, is the seventh most commonly prescribed drug in the United States. Because it's so widely used, the report predicts Americans will spend an additional $1.2 billion a year on three patented inhaler brands containing the new propellant (Ventolin, ProAir and Proventil) until generic versions reach pharmacies, probably after 2012. Patients who pay for their own medications will probably be hit hardest by new costs - paying on average $26 more per prescription, or $312 more per year - but people with prescription benefit plans will likely face higher co-pays as well, according to the review.
Additionally, while the new inhalers are just as effective as their traditional CFC counterparts, a few differences have been reported. One brand, for example, comes sealed in a protective pouch. After that pouch is opened, the drug carries a shelf life of just two months, while most inhalers can typically be stored for 15 to 24 months, Hendeles said.
Consumers will also notice that only the Ventolin brand of HFA inhaler comes with a counter to track how much medicine is left. For that reason, Hendeles suggests keeping a backup inhaler handy if physicians prescribe a device without a counter.
"There isn't any reliable way of estimating when they're going to run out," said Hendeles, who also serves as a consultant to the FDA.
The review also reports that some HFA inhalers tend to clog more easily. To prevent clogging in HFA inhalers, Hendeles advised, patients should remove the devices' metal canister once a week and clean the plastic actuators with warm water.
Not all of the new HFA inhaler products are ideal for everyone and health-care providers and their patients should be aware of important differences. Two brands of HFA inhalers contain ethanol. It may not be an appropriate therapy choice depending on the patient's religious beliefs, and can temporarily cause a false reading on breath alcohol tests performed by law enforcement agencies, Hendeles said.
Hendeles noted that CFC inhalers release negligible amounts of the propellant, and do not pose a threat to ozone depletion. However, the United States joined more than 185 other countries in signing the Montreal Protocol, an international treaty requiring complete withdrawal of all CFC products. The inhaler, deemed medically necessary, was exempt until new market replacements using HFA became available.
Hendeles said he hopes the review will dispel myths about HFA for doctors and patients. Still, even though HFA inhalers are safe for the environment and effective at treating asthma, some people may feel uncomfortable when making the switch. HFA inhalers spew slower and warmer plumes of medicine than their CFC counterparts, so asthma patients may fear their new inhalers aren't strong enough.
"There undoubtedly will be some people who are absolutely certain it doesn't work as well," Hendeles said, adding that patient education is the key to proper care.
Dr. Rachel L. Miller, an assistant professor of clinical medicine and public health at Columbia University, said she would urge asthma patients to consult their pharmacist or health-care provider if they're nervous about using the new inhalers.
"It's really the same drug," said Miller, who has worked with both CFC and HFA inhalers. "I have found both of them, in my personal experience, seem to work fine."
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