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Kathy Hitchens, PharmD, MSBA, is a medical writer who lives in Indianapolis.
As part of the 1987 international Montreal Protocol treaty to reduce/eliminate substances depleting the ozone layer, CFC (chlorofluorocarbon) propellants in albuterol metered-dose inhalers (MDIs) are gradually being replaced by HFAs (hydrofluoro-alkanes). The transition need not be complete until Dec. 31, 2008, when albuterol CFC-MDIs must be discontinued as mandated by the Food & Drug Administration. But the change is well under way. As Patty Johnson, spokeswoman for GlaxoSmithKline, noted, "We [GSK] already transitioned to Ventolin HFA MDI in early 2006."
Julie Lux, who is spokeswoman for Schering-Plough and its generic subsidiary Warrick Pharmaceuticals, acknowledged that her company is working on the transition, stepping up its production of Proventil HFA to meet existing needs while simultaneously reducing the production of CFC albuterol products. The plan is that sometime in the next few months, Warrick will completely cease production of generic albuterol.
Is this conversion expected to cause any drug shortages? Lux doesn't expect them. "Schering-Plough has been steadily working with the FDA over the past couple of years to ensure an adequate supply of the drug."
Warrick Pharmaceuticals has facilitated conversations about the transition by placing a prominent warning on albuterol packaging. It states: IMPORTANT: Inhalers like this one are being discontinued due to environmental impact. For more information, go to http://www.proventilhfa.com/ or call 1-877-hfa-7768.
The mechanics of the propellant transition are not as simple as one might think; CFC and HFA products are not generically equivalent. Changing propellants alters drug bioavailability. And not only are HFA-MDI drugs not bioequivalent to their CFC counterparts, they are not bio-equivalent to each other, either. Binaso commented, "The HFA products are all BX-rated-that is they're not substitutable for each other." As a result, pharmacists must contact prescribers to obtain new prescriptions.
The lack of bioequivalence also suggests that some patients may respond better to one branded inhaler than another. Ideally, transitioning the patient to an HFA inhaler now (while CFC-MDIs are still available) allows time to determine what works best. Binaso stated, "One thing we've learned over the years, I think, is that treatment has to be individualized."
Some patients who have already switched from CFC-to HFA-MDIs, have voiced concerns that the HFA products do not work. They don't feel the same "thrust" into their lungs from the HFA propellant as from the CFC propellant, they say. Studies have shown the products are effective; the HFA-delivered drug just "feels" different, Binaso commented. "That's where we have the opportunity to educate the patients that the technology has gotten better."
Binaso emphasized that the MDI transition is also an ideal opportunity for pharmacists "to provide counseling to the patient on the proper technique for using an inhaler." Published studies have repeatedly shown that many individuals do not use inhalers correctly, and with repeated use over time, attention to proper inhalation technique declines. Talking to an individual about his MDI also offers an opportunity for pharmaceutical care to assess asthma control. If an albuterol inhaler is being used for rescue more than two to three times a week, guidelines state, asthma is inadequately controlled and drug therapy may need to be modified.