5 Inhaler Tidbits You May Find Interesting
As I am doing research for the various articles I write, I often come upon neat little tidbits that have nothing to do with the project I’m working on. However, I like to save them so I can share them in posts like this. So, that said, here are 5 tidbits I learned about inhalers that you may find interesting.
Most inhaled medicine is wasted
You might be surprised to find out how little medicine gets to your lungs when you use your inhaler or take a breathing treatment. When metered dose inhalers (MDI) like albuterol are used, only 9% of the medicines makes it to your airways. However, when you use a spacer, this comes up to 15%. When a dry powder inhaler (DPI) like Advair is used, only 13% of the medicine makes it to your airways. When a small volume nebulizer is used, only 12% of the medicine makes it to your airways. So, this means that 85-91% of the medicine you inhale is wasted. Still, you must understand that the dose of the medicine is adjusted to account for this.1
HFA Inhalers seem to get deeper into your lungs compared to other inhalers
In order to reach the lower airways where it is needed, an inhaled medicine must be about 5 microns in size. According to studies, inhaler devices most likely to accomplish this are inhalers that use hydrofluoroalkane (HFA) as a propellant. Lung deposition by HFA inhalers is 50%. This is far greater than the old chlorofluorocarbon (CFC) inhalers, which achieved a 10-20% lung deposition. This is also better than DPIs, which achieve a lung deposition of 15-40%.2 This tidbit may prove useful for asthma physicians trying to help their asthma patients obtain ideal asthma control. It may also explain why medicines like Advair, long available as a dry powder inhaler (DPI) using the Diskus, are now available as HFA inhalers.
HFA inhalers may allow you to use lower doses of inhaled corticosteroids (ICS)
Since inhalers that use the HFA propellant allow for better lung distribution, this means that less medicine is needed to reach the lower airways. This would explain why HFA inhalers utilize a lower dose than the old CFC inhalers. This also may prove helpful for those experiencing systemic side effects with DPI devices. Switching to an HFA inhaler may allow for a lower dose to be used, resulting in fewer side effects.2
"Just switch inhaler devices"
Similarly, researchers have demonstrated differences in side effects from one inhaler device compared to another. For instance, metered dose inhalers have been shown to be more likely to cause dysphonia (hoarse voice) compared with DPIs. In this case, switching from one device to another may remedy the problem. The same has shown true for other side effects, so switching devices may be a better alternative to stopping a medicine that is needed to obtain ideal asthma control. In fact, here I can give an example from my own experience. When I was first introduced to the salmeterol (Serevent) inhaler in the early 1990s (it was a CFC inhaler at the time), I tolerated it poorly. However, when the Serevent Diskus was introduced to me, I tolerated it just fine. Today I get the same medicine in the combination inhaler Advair Diskus, and it has helped me obtain ideal asthma control. The point here is: don’t give up! If one inhaler device doesn’t work for you, talk to your doctor about trying another.
People with mild asthma may experience more side effects to inhaled medicine compared to those with moderate or severe asthma
When asthmatics with mild airway disease use inhalers, this may cause better medicine distribution, causing better results. However, this better distribution may also increase the risk of the medicine coming into contact with blood vessels in the lungs, resulting in a greater risk for systemic side effects. This may especially be true in people prescribed inhalers who have normal lungs (no airway obstruction) and are misdiagnosed with asthma.2 So, once it is assured that the asthmatic is using proper inhaler technique, is using a spacer (if indicated), and is rinsing after each use, complaints of side effects to a medicine may indicate the need to lower the dose or, perhaps, to discontinue therapy. This may especially be true for ICS.
Spacers may not cause better asthma control
While spacers have long been prescribed to improve inhaler coordination, they have also been prescribed to improve inhaler distribution to lungs. Various studies have shown both of these to be true. However, up until now, there has been scanty evidence that using a spacer with your asthma ICS inhaler results in improved asthma control. A study published in January, 2017, followed two groups of asthmatics for one year (5,068 asthmatics in total). The first group consisted of 2,534 asthmatics who used ICS inhalers without a spacer. The second group consisted of 2,534 asthmatics who used ICS inhalers with a spacer. Proper inhaler technique was assumed. After a year, it was determined that there was no difference in either group as far as asthma control or side effects. As noted, "This study found no evidence that spacer use led to an improved effectiveness of ICS delivered using a metered-dose inhaler." Of course this is just one study, and further studies were recommended to verify these results. Either way, it is the opinion of this author that you should still use a spacer with your MDI, as (to say it again) they have been proven to reduce side effects and improve lung distribution. still, this was an interesting study.
What to make of this?
Researchers are learning so much so fast about our disease, it’s easy for tidbits like these to go overlooked. So, if any or all of these were new to you, you are not alone. In fact, much of this is new to me too. Seriously! I mean, that’s the point of researching: to find wisdom that may have been overlooked that might asthmatics like us new topics to discuss with our asthma doctors. If wisdom like this helps one asthmatic obtain better asthma control, it’s well worth the effort.
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