Top 10 drugs 2024-25

[Music] Welcome to the Australian Prescriber Podcast. An independent, no-nonsense podcast for busy health professionals.

Hello and welcome to this special episode of the Australian Prescriber Podcast. We're here today to talk about what is an annual tradition at Australian Prescriber. We don't always do a podcast on it, the top 10 drugs for 2024-25, running through some of our key points in the way that we prescribe here in Australia. What are we prescribing a lot of? What is costing us money? What are the movements compared to a few years ago?

I'm David Liew. I'm one of your regular podcast hosts. I'm a clinical pharmacologist and rheumatologist here in Melbourne. I should say, first of all, everything I say today really just represents my personal opinions and not the opinions of the Drug Utilisation Sub Committee or have anything to do with the Australian Government. And Dhineli, who are you?

Hi everyone. I'm sure you might recognise me as I'm normally a host as well, and this is David and I hosting and interviewing at the same time. So bear with us as we navigate this newer territory.

Brave new world, Dhineli.

Yeah, that's right. So I'm a clinical pharmacist at a metropolitan quaternary hospital in Melbourne and have looked at the top 10 drugs in the past as well. My area of work is in antimicrobials, but obviously having worked in the area for a long time, I'm familiar with some of these and some of them I have no idea about. So I'll be on a learning curve with many of you listeners at the same time.

Last time that we did a podcast on this, it was you and me discussing the movements from now 3 years ago, but times change, prescribing changes. There's a lot that moves up and down and probably a lot with a move up and down in the next couple of years, but perhaps we can talk through some of the basics about what we are looking at in this annual tradition of Australian Prescriber, the top 10 drugs. Dhineli, what are we looking at?

Okay. So it's a pretty easy-looking paper to have a look at the online version. So there's 3 main tables. The first one [Table 1] is talking about the top 10 prescribed drugs on the PBS [Pharmaceutical Benefits Scheme] that are divided by their 'defined daily dose'. So a defined daily dose looks at a predefined amount that the WHO [World Health Organization] has defined as the expected [average] dose per day [for a drug used for its main indication in adults].

And then Table 2 is looking at more by prescription count. So prescription counts typically, a prescription will be for a month's supply for some of these more chronic conditions, and the table really reflects that. Most of the time, you're looking at one prescription a month, but then you do have exceptions to that. So there are some that are more frequently than once a month, some are less frequently or infrequent depending on whether, for example, an antimicrobial might be only when there is an infection. So we're looking strictly by prescription counts that come in and go through to the PBS for a claim.

For both these tables, I think it's worth pointing out that it's talking about items that are on the PBS. So there are many, many medications that are prescribed off the PBS where maybe a hospital foots the bill for it or perhaps it's a private prescription and the patient foots the bill for it. Those items would not be counted in this PBS tally. So I think it's worthwhile keeping those caveats in mind.

It's a really important proviso that these are only capturing PBS prescribing. Obviously, there are some big ticket items that we think about that get splashed around in the news. I can see on one of these tables, semaglutide, which is possibly the most talked about medicine in Australia right now, but the numbers that we see today only consider what's on the PBS, which currently is really for diabetes and diabetes only.

Yeah, exactly. So Table 3 extends that further and looks at the cost to the government. So a useful thing that's included in Table 3 is the cost and also includes the number of prescriptions. So while there might be some really big ticket items, there might only be a small number of scripts put through for that particular item, and that really highlights the expense of the individual drug. On the opposite end of the scale, there are somewhere there's a huge quantity that has gone through when you divide the cost by that number of scripts, it actually isn't so much. So when you look at the cost of the government, it's worth keeping in mind that it's talking about dollar value. And when you look at the number of scripts, you have to take that into account that it's not truly reflective of the actual individual cost for a single course.

Well, of course, Dhineli, the other thing to think about is the published cost that's made publicly available by the government doesn't reflect some of the other negotiations discounts that we might be receiving as a country. Obviously, this is something that's come into stark relief in recent times, but it's fair to say that the bargaining power of our government as a single payer and the apparatus of the PBS allows an Australian taxpayer to get as good value as possible, discussing with the manufacturers, by buying in bulk, and by negotiating situations. Often there are special agreements or caps in the background that we are not aware of, but all of us as taxpayers, we are the beneficiaries of. So that's all part of having a sustainable system in Australia. I think it's one of those things which we're incredibly lucky to have.

Oh, absolutely. If anyone has an opportunity to look at some of the universal healthcare systems that are across the world or lack thereof, I think it would really bring into focus just how lucky we are that this system is in place and that the checks and balances have been introduced to make it sustainable like you've mentioned, David. Because if it blows out, it could all fall apart and it might be completely pulled. So by keeping it sustainable and within reach of the government of being able to provide it, we're making it more accessible to everybody.

It really is the envy of a lot of countries in the world, our system. And I know internationally, a lot of people look to the PBS, PBAC [Pharmaceutical Benefits Advisory Committee], its system of critically evaluating the evidence that's provided and negotiations [of] cost and they look to Australia's system quite enviously as something that they would love to strive for in their own country.

So something to keep in mind and something to perhaps remind patients. For all clinicians out there that are dealing with patients on the front line, you can face a lot of questions about why does this cost as much? Why am I paying this much? It's never a bad idea to actually share what the true cost of the drug actually is, because it can give them maybe a bit more insight into what they're actually getting for their concession or their general price that they're paying each month.

Absolutely. It's important for us to all realise the cost of medicines. I just want to emphasise as well that it's, in my opinion, a very fair system in that the PBAC goes through a very regimented process in combination with manufacturers of medicines to make sure that everything is rigorously but fairly assessed and that we are actually doing the right thing in terms of bringing new medicines into the country so that people in Australia can benefit from really what is cutting edge pharmacotherapy. So thankfully, we've got a system that as it stands, delivers us the best of both worlds.

Absolutely. Looking now at the tables itself, I think the one thing that stands out to me, David, with table one anyway, the top 10 PBS drugs really haven't changed too much. There's been a little bit of movement up and down the ladder, but they really haven't fluctuated. You're really looking at cardiovascular disease being one of the biggest drivers of a lot of the top 10 PBS drugs.

And when I say cardiovascular disease, I mean all of the arms involved with that. So the type 2 diabetes that leads to a lot of the cardiovascular disease or usually goes hand in hand. So most of the drugs there are really reflective of that largely being statins, blood pressure medications and all the different classes that are available in those.

And then the other thing that seems to be consistently represented both from '22 right across to 2025 is a few of the SSRIs that seem to be consistently there. They haven't changed as to which ones are being prescribed. So the fact that we are probably not changing practise too much is not a bad thing. It's probably saying that we are prescribing by the guidelines. Because most of these medications are considered first-line agents for their separate indications and reflective of the chronic disease that we're seeing in Australia itself.

Well, with cardiovascular medicines, I guess it's really important for us to not get complacent about it, because there's just so much benefit in terms of managing our cardiovascular burden in this country from appropriate pharmacotherapy prevention.

Absolutely. Especially when we know in terms of statistically what it contributes to our overall mortality and morbidity across the country.

It's also interesting to see that the SSRIs have been stable. I realise that we've come through a particularly difficult six years [COVID-19]. Things have changed around and also there have been some various different questions which have not necessarily been substantiated about SSRIs. So I think that we can see that stability in prescribing suggests that we are really sticking to guidelines and that we are prescribing in an evidence-based manner. I'm sure we can always do better, but we're not doing too badly right now.

Yeah, exactly. I think it's a really fair reflection of the current chronic diseases and chronic conditions that the majority of Australians are really going through at the moment.

I guess putting my own interest area into focus here with Table 2, the fact that there are 2 antimicrobials there that make it to the top 10 is interesting to me. I'm really comforted by the fact that they're not broad spectrum, that they are first line agents for many of the indications in the Therapeutic Guidelines for antimicrobials. So to me, this suggests that we are sticking to guidelines again, especially with amoxicillin. I think there's always concern that we prescribe a lot more broader or even as far as amoxicillin + clavulanic acid as first line where it shouldn't be.

But looking at these numbers, it really suggests that largely, we are sticking to our first line recommended agents, which is excellent and comforting to see. So I guess when it comes to the first 2 tables, I don't really think that there's any surprises there. It's just a little bit of fluctuation as to up and down on those ladders, but nothing that stands out as being particularly of concern or of pattern change between 2022 to 2025.

I mean, enormous credit to our primary care prescribers for being able to maintain the use of antibiotics in the way that they do and making sure that we do steward the system. And I think enormous credit as well to the people who have worked so hard at a policy level and at a research level on antimicrobial stewardship, because once again, it's something that this country can be very proud of.

Yeah, absolutely. Going to Table 3 now, this is probably the most interesting of all of them given that we're talking about dollars and costs to government, but we're talking about medications that are definitely not as widely prescribed yet are the most expensive on the PBS. I might throw to you here David, because there's a lot of medications here that are really unfamiliar to me. Do you mind running us through what a couple of them are in terms of the biologics and the monoclonal antibodies?

Sure. Well, before we get onto that, I think you can divide the top 10 by cost and keeping in mind this is the list price cost. You can divide the top 10 by cost really into 2 rough categories and I'd say that there were some modestly expensive but heavily used medicines. And then there are some which are highly specialised and the prescribing base is limited. They can be highly impactful but also come at high cost.

We've seen this dichotomy over the years. So in that first category, we've got medicines which I think many people will be familiar with. Denosumab for osteoporosis, apixaban the anticoagulant, and then the aforementioned semaglutide, which unless you've been living underneath a rock, you'll have heard about.

And to give you an idea of the kind of numbers, apixaban, we're talking 4.3 million prescriptions, so that's really just outside the top 10. We're talking about something which is very commonly prescribed, something that's obviously come to dominate its class, but it has enormous impact in the right set of people and hence why it's used on-scale. Same with semaglutide and denosumab. It's clearly important that we steward the use of these medicines because you can imagine how any of those 3 medicines, if we don't apply a quality use of medicine lens to the way we prescribe, then [the cost of] those things can blow out.

I think one of the things that might not be in the memory of the newer prescribers that haven't been prescribing anticoagulants maybe 10 years ago, but apixaban really revolutionised the landscape for oral anticoagulation and its class, all the DOACs. And the fact that we even have access to it now has completely changed things for the patient in terms of the testing that's required, in terms of the monitoring and the dose adjustments. Warfarin, which was pretty much the only thing available to us at the time was very difficult for a lot of patients to manage and very dangerous because of that.

So I think really celebrating the fact that apixaban is there. It's kind of just completely changed it. And I can see now if you compare to our previous years, there's been quite a price drop too in terms of its cost notwithstanding all the caveats that you've mentioned prior. But the fact that not only do we have access to it but it's becoming more affordable to the government really means that this is the game changer that's here to stay and it's really a positive thing for both patient and prescriber and the government too.

It's the kind of thing that once again with the top 10 lists, you can go back decades and you can see obviously as much as some of the medicines are the same, some of them are substantially different, especially in this cost list. I'm sure that we will see movements in some of these medicines in the future.

Yeah, absolutely. Now on to the other ones, the weird ones. Pull me through those, David.

Weird ones are my friends, Dhineli.

I know that's why you are going to talk about them.

Well, there are some medicines on there and we've seen some of these trends in the past of medicines used by highly specialised situations. And so in amongst there, we've got a few who have been there for a long time, so I can see aflibercept there at number 5. It's been there for quite a long time. Obviously, our ophthalmology colleagues very familiar with its use. It's quite unfamiliar to those outside. And actually, the numbers in the overall utilisation has been fairly stable it seems by these charts.

Stable. Yeah.

So then there are some others which were slightly newer but also still quite ever-present. So you can see on there elexacaftor with tezacaftor and ivacaftor, which is used in the context of cystic fibrosis and is enormously impactful there. And we've seen that on the list for some time, but you don't have to go back that far to see it not present. Clearly, it has led to a complete paradigm change in those people, but very small numbers in the scheme of the PBS.

So 29,000 prescriptions knowing that every individual has multiple prescriptions there. So that's that other end of things. But then 2 of the main categories that we've often seen on these lists are what I'd call immunomodulatory therapies. And so in this case, we've got ustekinumab, we've got dupilumab and we've got upadacitinib, some for autoimmune indications there, some for allergic indications. And so those have been a long-standing feature, although the exact individual medicines on there has changed around a little bit over time.

Upadacitinib is a new entrant to that list and we'll get to that in a bit. And then for certainly the last nearly 10 years now, we've seen the checkpoint inhibitors feature here and the 2 most used checkpoint inhibitors by volume, pembrolizumab at the top and nivolumab at number 6. And these are cancer immunotherapy medicines, which once again have completely revolutionised a lot of different tumour streams in oncology. Have led to a lot of people living a lot longer than they would have.

All of these of course do make cost-effectiveness sense, do make pharmacoeconomic sense. So even though they're relatively small numbers, you can imagine what that means in terms of impact for individual patients. So in a way, it's same, same but different. We have obviously seen these ever-present themes to these high-cost medicines, but a medicine like upadacitinib, which is an oral agent, it's a JAK inhibitor, it's made its way onto the list. It's listed for a number of different autoimmune conditions. I think notable amongst it is that it does have a black box warning because in a study was compared against, TNF [tumour necrosis factor] inhibitors and rheumatoid arthritis patients and in that cohort of cardiovascularly enriched patients, it did seem to lead to an incrementally increased risk of cardiovascular risk and cancer compared to TNF inhibitors.

But in certain situations, it's clearly the best option. And in fact, there are plenty of situations where it is the one thing that our patients are relying on. So in amongst it all, each of those medicines has its own individual nuance.

And what are your thoughts on changes that you might expect to see for next year? Are there upcoming agents in this sphere of monoclonals and biologic agents they might appear on this list?

Well, Dhineli, not only is it a fool's game to try and predict anything, but I certainly wouldn't want to try and get ahead of where the new approvals might come onto the list. And I think new approvals could certainly change this order. I think as well we often see you require time to get full uptake of a medicine to the expected levels. And there is a lot within the PBAC apparatus to try and predict this and understand about the financial impact on the taxpayer and also of course the impact on quality use of medicines because a key part of medicines is understanding how we can use them well and how we can ensure that they're being used appropriately. I guess we have gone out of an era where we did have a lot of rockets. And I think particularly, one of the medicines that's dropped off this list is molnupiravir.

Yes. As well as nirmatrelvir and ritonavir. So both of them have dropped off, which I think really speaks to a lot of things when it comes to COVID.

So we saw molnupiravir on the last set of lists when we had this discussion. And of course, we saw a molnupiravir still on the list. Last time, nirmatrelvir-ritonavir combination had dropped off a little bit before then. But if you go back a few years to the height of the COVID-19 pandemic, we saw those really up there in terms of impact on the budget. Do you think it's going to always be that way? Do you think that was a, that we saw this high use of antivirals, or do you think that kind of thing might happen again in the future or maybe outside of a pandemic situation?

I think outside of a pandemic, I don't think we will see this happen again. I think we really saw it being reached for as an agent that would try and keep people out of hospital. That was really the number one aim. And if you look at the criteria for prescribing them, it has to be for someone that's not about to go to hospital.

It's worth commenting that both these medications only went onto the PBS in 2022. So in 2020 and 2021, whenever they did come out, they were really only accessible via a hospital. There's a lot of kerfuffle about criteria to be met in order to prescribe them because they are expensive, they're not cheap. And we can say that when they went on the PBS, they shot up. Molnupiravir shot up to number one in the 2022-23 period.

So a couple of things to comment on here. COVID as an infection that's causing significant morbidity has really dropped off this year in particular. So 2025 has seen a huge flux of influenza and at our local hospital there was a 4 to 5 fold difference in the presentations with influenza versus COVID. So when it comes to the frequency of the infection itself, that has dropped off. Its severity and its virulence, ability to make people particularly sick has also dropped off, also a good thing.

So I don't think we'll see these agents in the top 10 again unless we find that they're useful in a different pandemic, in a different setting, because they're not on the PBS for any other indication and we don't even prescribe them off label for any other indications.

Obviously, nirmatrelvir and ritonavir are used separately for HIV infection, but that's in a very different dosing and schedule versus molnupiravir, which is not used for anything else. Molnupiravir probably had the least amount of evidence to back its use, but it was the safest. So I think that's why it was often reached for in that 2022 period, '23, it's the most expensive medication to the government because it was in the height of the pandemic or towards the end of it, but really where we had these drugs available to us and it was the safest to use versus nirmatrelvir-ritonavir, which was laced with lots of drug interactions and made it a little bit more trickier and difficult to prescribe, especially for patients with lots of comorbidities.

So I would love to say that we will never see that ever happen again, but I think it's reflective really just of what we saw in that period. And if we were to go through another pandemic, I think it would be not surprising if we ended up seeing either these or other antivirals or antimicrobials will start make it to the top 10 again. Because the aim of the game was to keep people as well as possible out of hospital to take pressure off that system.

Absolutely. I mean, it goes to show that there is strategy behind all of this. As we should have in our health system to be able to extract the maximum value so that we as taxpayers are happy, but then we as consumers of the system and our patients are also happy that they're getting a fair deal. So it's always interesting that we can have a look at what medicines are being used. I suspect we'll see some very interesting changes in the next few years, but I won't try and anticipate that. We'll just have to tune in a couple of years time when Dhineli and I do this again.

Sounds good. Thank you so much, David, for your time to discuss this. It's always interesting and I do like the look back. I think readers will find that interesting to click back and have a look at the previous years and compare it for themselves.

Dhineli, it's always a pleasure chatting.

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The views of the guests and the hosts on this podcast are their own and may not represent Australian Prescriber or Therapeutic Guidelines. Dhineli has no disclosures and I'm a member of the Drug Utilisation Self-Companies of the Pharmaceutical Benefits Advisory Committee. I'm David Liew. That was Dhineli Perera. And once again, thank you so much for joining us on the Australian Prescriber Podcast.