The NEJM on HFA inhalers

As a followup to my post the other day…

The NEJM concludes — along with the rest of the world — that HFA albuterol formulations are more expensive than their CFC counterparts. The article (subscription required) delves into some of the differences between the various HFA formulations as well as the differences between CFC and HFA albuterol.

The article doesn’t talk much about ProAir HFA, which I find a bit strange, especially as it has captured 60% of the HFA albuterol market. Unrelatedly, it seems that concentrations of albuterol are slightly higher with HFA than the CFC versions, despite the smaller plume.

Here’re some semi-relevant differences between Ventolin HFA and Proventil HFA, emphasis mine:

The excipients added to the propellant formulation differ according to the brand of HFA inhaler. For instance, each puff of Proventil HFA releases 4 μl of ethanol. This small amount of ethanol will not have a discernible clinical effect, but it may be of concern for patients who for religious or other reasons abstain from alcohol. Breathalcohol levels of up to 35 μg per 100 ml may be detected for up to 5 minutes after two puffs of Proventil HFA. Unlike CFC propellants, HFA propellants may cause false positive readings in anesthetic gas–monitoring systems. The infrared spectrums of HFA overlap with commonly used anesthetic gases in the range of 8 to 12 μm. One albuterol product, Ventolin HFA, contains no excipients other than the propellant, a characteristic that may improve tolerability for some patients. However, Ventolin HFA comes packaged in a moisture-resistant protective pouch containing a dessicant and has a limited shelf life once it has been removed from the pouch. Ventolin HFAs have a greater affinity for moisture than do CFCs, which means that water vapor is more likely to enter the canister around the meteringvalve gaskets. The other approved HFA inhalers are less susceptible to moisture permeation and do not require a protective pouch.

Shelf life for Ventolin HFA is 2 months after opening, so it’s a mixed bag.

A breakdown:

Comparison of Albuterol HFA formulations

[tags]Medicine, pharmacy, albuterol, HFA, CFC[/tags]

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