Inhaler device selection for people with asthma or chronic obstructive pulmonary disease

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In my GP consulting room, I have a poster showing all 42 inhalers available in Australia to treat asthma and chronic obstructive pulmonary disease, COPD. It's big, colourful, and often commented on. Patients ask me, ‘Why are there so many options?’ Today on the Australian Prescriber Podcast, we are delving into part of the answer. Pharmacist, Deborah Rigby, will help us understand which inhaler device we should use, when, and why. There are many options, each with their own specific characteristics, as well as benefits and limitations. Debbie is an advanced practise pharmacist and asthma educator, working directly with patients, as well as a clinical executive lead with the National Asthma Council and Academic at the University of Queensland and QUT, and I'm Dr Laura Beaton your GP host for today. Debbie, thank you so much and welcome to the show.

Thank you, Laura. Thank you for having me.

To start off with, why do we have so many options?

You're right. There are a lot of options, and I think that's actually quite good. I know it's confusing, both for patients, as well as doctors and pharmacists. I often get asked, ‘What's the best inhaler?’ And I'll always say the best inhaler is the one the patient can and will use, so by having lots of different options, we can tailor our choices of the inhalers to the patient's preference. Yes, you might have your favourite one that you are comfortable with demonstrating to the patient, but at the end of the day, it is about what the patient can and will use.

That's a great message to carry throughout this podcast today. I know in asthma and COPD care, there are lots of different medication classes, but just setting that aside, if the medication inside the different devices is exactly the same, why is it important clinically how the medications are delivered into the lungs?

I think the advantage of any inhalers is that it's a smaller dose than perhaps you would be using if you're taking it orally and therefore less likely to have systemic side effects, but it needs to go to where it needs to work, which is in the lungs, and in particular in the small airways of the lungs. So, there are lots and lots of different choices, but it's really optimising that delivery to the lungs, giving the greatest lung deposition and, therefore, the benefits of those medicines.

It sounds like it's not just the medication itself. It's actually ensuring that it gets to where it needs to act, is something we need to take into account.

That's right. Yes, the medicines work, but it's really helpful for the patient to understand the differences between them [inhalers], and help them to understand why certain steps are important, and feel confident or even master those steps in actually using the inhalers correctly.

That will move us to our next section, which is really starting to talk about these different inhalers, because another message of your article is that, unless we know how they work, and people know how to actually use them properly, if you don't get the medicine down to where it needs to act, it's not going to be very effective.

Correct.

Now, this is a podcast, so we can't do show and tell about what each inhaler type looks like, but we're going to do our best to describe them. When thinking about respiratory care, I'm sure the type most people think about are the pressured metered dose inhalers [pMDIs]. This is that classic blue puffer that's been ubiquitous for so long in respiratory care, and these are little vertical devices that have a canister with a propellant, and ideally, they are used with the spacer. So if we could set that one aside, what are the other types that we have?

So the pMDI [pressured metered dose inhalers], which is the easiest way to say it, they have been around for a long time, but in more recent years, the last couple of decades we've seen these other types of inhalers. Part of the reason for that is the fact that we've got a greater awareness of climate change and the impact that the propellant in the pMDIs have on the environment. So the types that we have, it's largely put into 3 different types. So we've got pMDIs, and within that, we've got breath-actuated pMDIs, which then dry powder inhalers, which don't contain the propellant, and they just have the active ingredient as a powder, mixed with other excipients like lactose. Then, the third type is the soft mist inhaler, and we only have one type of those in Australia, called a Respimat.

Thinking about the pMDIs, how is a breath-actuated different from the other type?

So the classic pMDI, the biggest challenge for patients is to coordinate their actuation, so pressing down on the canister to release the metered dose, and their inhalation. So that actuation, inhalation coordination is very challenging. Vast majority of people really struggle with it, and that's one of the reasons why we should be using a spacer, whereas the breath-actuated pMDI, the Autohaler, yes, you load the dose, but your breathing in actually releases that dose. So it's, as the name says, breath-actuated, so that coordination, which is the most challenging part with traditional pMDIs, is not part of the steps.

And I understand we have one type of soft mist inhaler available in Australia, but in the dry powder inhalers, there are a few different types of how that medication is loaded into the device that might impact whether it's the right choice for a patient. What are the different types of dry powder inhalers available?

So there's 3 types of dry powder inhalers. One comes with a capsule in a separate bottle or a foil strip, and the patient has to take that out and then load it into the device for each inhalation. The other ones are sort of closed devices, but even inside them there's 2 different types. So one is what's called a multi-dose or a reservoir, where all the 120 or 60 doses are in a reservoir or a chamber within the device, and the third type is where the metered dose is contained within a foil pack, which is wound, circular inside the inhaler.

It's a little bit technical, but I think, from the perspective of the patient and the patient's choice or what they can master, for example, the ones with the capsules, and they're the ones like the traditional Handi-halers, and now have breeze inhalers, and some generic forms, like a Zonda, the patient's dexterity and their ability to actually peel off the foil pack and get the tiny capsule out might be compromised by their dexterity or other medical conditions, like having a tremor or Parkinson's disease, so that might not be the most appropriate device for an individual patient.

And those patient factors, like someone's manual dexterity or their ability to coordinate breath in at the same time of pressing their inhaler in, these are all these factors that we need to really think about when choosing a inhaler device. What are the main factors that you consider when thinking which option might be right?

I think with the pMDI, that coordination between actuation and inhalation is critical. Yes, we can say you should always use a spacer. It's not just children that should be using spacers, but everybody, ideally, and especially in adults, perhaps older population, again, with those cognitive or dexterity issues. I think the second most important thing, which is applicable across all of the different types of inhalers, is a patient's inspiratory effort. So with the pMDIs and the soft mist inhaler, the inspiratory flow rate, so the speed and amount of effort the patient uses for the pMDIs and the SMIs is lower, but they need to slow that breath down. It should be a slow and steady inhalation, ideally over 3 to 5 seconds. Most patients will do it way too quick. They'll just do that really quick inhalation, and most of it is impacting on the oropharyngeal area.

Whereas with all of the dry powder inhalers, the inhalation needs to be quick and deep, over 2 to 3 seconds, and that first second of inhalation needs to be the most forceful. The reason for that is there's no propellant in it, and the active ingredient powder is mixed with other excipients, mostly lactose. So what you're trying to do with that quick and deep inhalation is separate the active ingredient, which is small particle size, 1 to 5 microns, from the lactose, which has a much larger particle size, 10 to 20 microns, and separate the active ingredient into those small particle sizes so that it is inhaled into the lungs and, in particular, into those small airways, whereas the lactose, you don't actually want to inhale that, and the large particle size is impacted in the oropharyngeal area. So that's separation or de-agglomeration of the active ingredient from the excipient is really critical to getting that optimal lung deposition.

So in clinic, if sitting in front of you, someone can take a really short, sharp, deep breath over 2 to 3 seconds, and they're having a good effort, they would probably be appropriate for a DPI [dry powder inhaler] or at least a trial?

Yeah. I think, and the evidence supports this as well as clinical experience. Most patients can master a dry powder inhaler. Very young children might struggle with it. Children over the age of 6 and over, most of them can be done with coaching from parents or carers, and certainly, older people who may have reduced lung capacity because of their asthma or COPD, majority of those can be taught to use it with that training. What else are we considering when thinking which inhaler device is going to be best? I think the other factor is really the environmental impact of these inhalers. So with the pMDIs, they contain a propellant. Yes, they don't contain the old CFC propellants anymore, which were phased out because of their impact on the ozone layer, but the current propellants used across all the pMDIs do have a carbon footprint, and they certainly have a higher carbon footprint compared to the soft mist inhaler, which doesn't contain a propellant and the dry powder inhalers.

Your article talks about how, when we're reviewing someone's asthma care and thinking about the best choice for them, that's actually a really great opportunity to improve also the quality of care. It's not just about the environmental impact that's part of it, but also to make sure that they're having a device that's going to suit them better. With the PBS guideline changes in 2020 for asthma, and how the anti-inflammatory combination preventer-reliever dry powder inhalers now, listing for people who have even mild asthma, it's such a win-win-win where people are getting better asthma control, their asthma care is having much less of a carbon footprint. They're probably actually spending less money on their asthma treatment, because they're getting better control.

Yeah, and we still do have a problem in Australia and worldwide with overuse or over-reliance on short-acting β₂ adrenergic (SABAs), like salbutamol. They're only, in Australia, delivered through a pMDI, and we know also that that's no longer considered first-line therapy for adults and adolescents, so really trying to bring it all together and say that we've got this overuse of SABAs, and the shift towards ‘anti-inflammatory reliever’ therapy, or ‘AIR’ therapy, where people are using an ICS formoterol product, ideally as a dry powder inhaler. It has to be formoterol as a long-acting β₂ agonist, because formoterol, yes, it's long-acting, it lasts at least 12 hours, but it also has a fast onset of action.

So its onset of action is just the same as salbutamol. It works within 3 to 5 minutes, just as effective as Salbutamol in controlling patient symptoms, so guidelines are changing around the world based on the evidence. We've got extensive evidence now on the benefits of anti-inflammatory reliever therapy, compared to just relying on SABAs. So it reduces the risk of exacerbations, severe exacerbations, as well as hospitalizations and ED visits, so I think that's part of the conversation we should be having with pharmacists, as well as with our patients and helping them to understand the potential harm associated with relying just on SABAs.

And your article mentions that, at the end of life of a pMDI, we really need to be thinking about safe disposal of those.

Yeah, yeah. Because many people would just throw it into their normal rubbish, and then it goes into the landfill. The propellant that is contained, even if you've finished all the doses, there's still some propellant left in a pMDI, so that will slowly leak out into the atmosphere, into the environment. If it's in landfill, at the National Asthma Council, we're really encouraging patients to take back their finished or unused, unwanted inhalers, all of the inhalers, not just the pMDIs, to a community pharmacy, because there is a government funded programme which allows for that safe disposal of medicines, as well as inhalers, by using high temperature incineration.

So now, once we've selected an appropriate inhaler and we've made this shared decision with our patients, what do you recommend for ensuring the correct technique? I was really shocked to read in the article that, actually, probably 10% of people are using their inhaler competently.

Yeah. It's a frightening statistic, and perhaps more frightening is the one that only probably 40 to 50% of health professionals know how to use every single one of these inhalers correctly. So as health professionals, we need to feel confident and competent to demonstrate it to patients. There are videos available on many websites, including the National Asthma Council website to show patients, if you don't feel confident yourself in demonstrating it to a patient, and I find that patients need to see them more than once, so it's useful to give them the link or show them where they can find those videos.

Research has shown that patients, even if they master it at that visit with you, within 2 to 3 months, they've forgotten some steps. So they're not really on top of it, and I think that's where pharmacists play a big role, because patients are coming back to the pharmacy every month, or now every 2 months perhaps with 60-day dispensing. And we should be asking and hoping that patients will feel comfortable to demonstrate their inhaler technique in a pharmacy. I do Home Medicine Reviews, and many patients will feel more comfortable demonstrating that in the comfort of their own home, so that's another option. All GPs can refer for a Home Medicine Review, and then a pharmacist can do it in the privacy of the person's home.

It's great to highlight the multidisciplinary nature of asthma care, and I will also second your recommendation for the how-to videos on the National Asthma Council website. That's my go-to SMS link to patient and carer at the end of consultation about asthma. Thank you, Debbie, for this article and such a great chat today. It's been great to speak through the details of inhaler device choice and also keep a focus on the fact that good asthma and COPD care really needs to involve patients in the decision-making, because as you said, the inhaler that they can and will use is probably the best for them. I'll direct everybody to your excellent article, which is free on the Australian Prescriber website. There's a detailed Table 2, which goes through all of the advantages and disadvantages of the inhalers, as well as excellent diagrams. If listening to us talk about the inhalers today is leaving you more confused, please look at the article and see those diagrams.

Thank you for the chat today. I think it's a really important issue, and I think inhaler choice is just as important as the medicine choice. So, we do have a lot of different devices. But I think the overarching message is around patient's choice, and what they're comfortable and competent to be able to use, and that's the beauty of having so many different choices now.

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The views of the hosts and guests on this podcast are their own and may not represent Australian prescriber or therapeutic guidelines. Deborah Rigby has received payment from the Lung Foundation Australia for work on a COPD E-learning project, and honoraria from AstraZeneca, Boehringer Ingelheim, Care Pharmaceuticals, Chiesi, GSK, Menarini, Moderna, MSD, Mundipharma, Respiri, Teva, and Viatris for presentations, conferences, travel, or advisory board roles. Deborah is a member of the Lung Foundation Australia's COPD Clinical Advisory Committee and Primary Care COPD Advisory Committee, the Pharmaceutical Society of Australia's Respiratory Task Force, and the Australian Commission for Quality and Safety in Health Care's COPD Clinical Care Standard Topic Working Group and Indicators Working Group.