The RAASi reset

The For Kidneys Sake podcast series is brought to you by Imperial College Healthcare NHS Trust and North West London Integrated Care Board (NWL NHS).

In this episode, Jeremy and Andrew revisit one of the most fundamental yet persistently misunderstood areas in kidney care: the use and misuse of renin–angiotensin system inhibitors (RAASIs). Despite being cheap, powerful, and backed by decades of evidence, these cornerstone drugs remain under-dosed, frequently interrupted, and poorly optimised in real-world practice. The hosts examine why so many patients remain on subtherapeutic doses, how unnecessary caution and slow titration in primary care can blunt benefits, and why maximal dosing matters far more than blood pressure alone.

They then take listeners through the “patient journey” of being on a RAASI, exploring predictable bumps in the road, especially hyperkalemia and how proactive preparation could prevent the all-too-common cycle of unnecessary emergency visits and abrupt drug cessation. They unpack practical strategies: identifying high-risk patients, simple steps to minimise potassium rises, the role of constipation and diet, and the increasingly important place of modern potassium binders. Ultimately, Jeremy and Andrew make a compelling case: RAASIs only work when the patient actually stays on them, and with the right approach, nearly every patient can.

Top 5 Takeaways

1️⃣ Maximal doses matter — Subtherapeutic RAASI dosing is common, but full doses offer far greater cardio-renal protection than BP reductions alone.
2️⃣ Titrate faster — safely — Most patients can start on higher doses (e.g., Ramipril 5 mg, not 1.25 mg). Slow, cautious uptitration often delays benefits.
3️⃣ Hyperkalemia is predictable, not surprising — It’s a physiologic effect of RAAS blockade, not an adverse event. High-risk patients can be anticipated.
4️⃣ Prepare patients for the journey — Early education on potassium, diet, constipation, and reversible triggers prevents unnecessary drug interruption.
5️⃣ Don’t stop RAASIs too quickly — Most potassium rises are fixable; newer potassium binders allow continued, safe use of ACEi/ARB therapy.

Resource Links:
NICE GUIDELINES [NG203] chronic kidney disease: assessment and management Overview | Chronic kidney disease: assessment and management | Guidance | NICE

Northwest London CKD guidelines for primary care Chronic kidney disease (nwlondonicb.nhs.uk)

CaReMe UK - British Cardiovascular Society

The purpose of this podcast is to inform and educate health care professionals working in the primary care and community setting. The content is evidence based and consistent with NICE guidelines and North West Guidelines available at the time of publication.

The content of this podcast does not constitute medical advice and it is not intended to function as a substitute for a healthcare practitioner’s judgement.

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Produced by award-winning media and marketing specialist Heather Pownall of Heather's Media Hub

Chapters

• 0:35 Introduction & Why RAASi Still Matter
• 2:27 Why Maximal Dosing Is Critical
• 5:23 Hyperkalaemia: A Predictable, Manageable Risk
• 8:18 Managing Disruptions & Using Potassium Binders
• 11:25 Sick Day Rules, Restarting RAASi & Key Takeaways

Transcript

Jeremy Levy 
So, hello, I'm Jeremy Levy, consultant nephrologist at Imperial NHS Trust.

Andrew 
Hi, I'm Andrew Frankel, a colleague of Jeremy's working also at Imperial College Healthcare NHS Trust, and welcome to another podcast in our series for kidneys sake.

Jeremy Levy 
That's right. And today's episode actually, we've decided to pick this topic because we've been asked this by fans. We should call them fans out there, but listeners who've been emailing in. So if you subscribe to our newsletter, you're welcome to email us with other possible topics for future podcasts. So way back in the early days of our podcast series, which was only last year, we did talk about drug treatment for chronic kidney disease, which of course included a discussion about renin.

Angiotensin system inhibitors or RAASi, which are of course the ACE inhibitors and the Angiotensin receptor blockers, the ARBs. And we talked about those at length. And currently there's been a lot more emphasis on some of these newer sexier drugs such as the SGLT2 inhibitors and finerenone. So actually we often forget the basics about the use of the RAASi's because they've been around also for 30 years. And I know that Andrew especially has a very strong view that we really don't manage the use of these drugs well enough and to maximise their benefits in patients with both chronic kidney disease and actually the broader cardio renal metabolic syndromes but these are cheap and really really effective drugs so can we do better how should we manage sick day guidance what do we do about interrupting the medicines and we should all be experts at managing potassium but it remains a problem

And you should all have listened to the very first episode we did last year which was specifically about potassium but all of this range of topics we've been asked more and more questions about.

Andrew 
Yes, Jeremy, and you've definitely touched a nerve there for me as this is an area that I think is so important. And there are a number of issues relating to the use of this group of drugs. We're going to call them RAASi. And although we think lots of our patients are getting benefit from these agents, many are not getting nearly as much benefit as they should be.

Jeremy Levy 
That's right. And we really want patients to maximise the benefits from these really, really important drugs. And actually, I think we don't really talk about a patient's journey in relation to these drugs. We sort of just give them and then sort of forget it. primary care often is wedded to really, really cautious, slow, incremental introduction of rashes. And that's a problem.

There's this fantastic website CVD Cardiovascular Disease Prevent, which shows data from across the UK about prescribing and other things. And if you look, many, many patients are on these drugs, the RAASi's, which is really, really good. But sadly, the majority are on actually low doses. And at the very beginning in our initial podcast, we talked about this, that very low doses aren't enough. Yes, of course they help. But there's really good evidence that you need to be on maximal doses for maximal benefits for cardio renal protection. And if you're on 1.25 milligrams of Rampril, it's really not doing enough for your kidneys. So to remind you all, using maximal doses of all of the RAASi's, whichever one you're using, offers a cardio renal protection, protection from progressive chronic kidney disease, way above the blood pressure lowering effects alone. So if you've got a patient with chronic kidney disease and their systolic blood pressure is say 130, which you might be happy with, going up to maximum doses of the RAASi, whichever one you're on, will offer more kidney protection, even though the blood pressure may not drop further, and even if it does, but it's about protection within the kidneys for maximum doses.

Andrew 
And of course, Jeremy, we shouldn't be siloed. It isn't just the kidney protection. It's the cardiovascular protection, which is also key to this. we talked in that first episode about the introduction of these drugs. So if you start the journey, the introduction of the drugs is... It's so often that these drugs are introduced slowly over time, incrementally, and we highlighted that it's quite safe, if the patient is robust to introduce these drugs more rapidly. So start with say Ramapril of 5, not 1.25 or Urbasart on 150, not 75 and increase rapidly to maximal dose. And I have to say, I know that our pharmacy colleagues and our nurses are so much better at medicines introduction and medicines optimisation than doctors.

Jeremy Levy 
They are indeed. They follow advice much better as well. So Andrew, is there a problem beyond this? So getting patients onto maximal doses and doing that quickly. But once the patient's on a maximal dose, what's the problem there after?

Andrew
Yeah, this is where we talk about the journey because I think many patients have a fairly interrupted journey. It's a good way to view this and to think about the disruptors of that journey. Those disruptors include the issues that we've also covered previously, such as changing kidney function, but most particularly, hypertasin or hyperkalemia.

Perhaps the most important place to start or to advise primary care where to start is preparation. And I know Jeremy that when you go on your journeys, whether that be by bicycle or on two legs, which is less common, one of the things I'm sure you do is prepare. And I don't think we prepare patients for this journey nearly as effectively as we should.

Jeremy Levy 
I'm not sure I prepared myself, Andrew, but I think you're absolutely right. So let's first touch on hyperkalemia, because we've talked about that before, but it remains a really, really important topic. I suppose the point you're making here really is that we should think about this really not as an adverse event, but as a completely predictable event. You're giving patients a drug that blocks the hormone system that will cause the potassium to rise. And so it's not really an adverse effect at all.

So we could be much better at preparing patients to say, it might be that your potassium is going to rise and actually to minimise that. And there are some simple things that people can do to make sure this isn't a problem and that true hyperkalemia, which is problematic, doesn't occur. Because actually it's not too difficult to predict the patients who are likely to have a problem.

They're the ones with the most severe kidney disease, particularly all the most severe heart failure, and especially in the context of diabetes for various reasons. But also look at the other treatments patients are on. So, for example, being on non-steroidal can sometimes make that worse. And then simple maneuvers. And Andrew reminded me of this, which I hadn't always remembered. But, you know, patients who are more constipated actually run into more problems with hyperkalemia.

And talking about diet, and we don't want people to be on a potassium restricted diet, but if somebody is on a higher potassium diet, then just being cautious about what they're eating will be very, very important and encourage them to think about the foods that they're eating.

Andrew 
That is important. And I believe that advice needs to be given in conjunction with advice that is delivered to the patient so that they understand why they're on the drug and the benefits it provides. Simply warning the patient the potassium may rise is going to be important. And also this can be managed relatively easily is also important. The problem is that when a high potassium occurs, and the GP feels the need to send the patient to the emergency department, that is where the greatest disruption occurs. People have their treatments stopped, communication to patients is often poor, explaining what has happened and why changes are being made. then communication to primary care is equally poor, leaving primary care uncertain as to how to manage the patients and get the patients back on these effective treatments. So, understanding these issues are important but also making sure that patients understand that these issues can occur and that it's important they are maintained on these effective drugs.

Jeremy Levy 
That's absolutely right. And I think if we can get patients to remember that then it might be more likely they get back on it because of course when hyperkalemia, true hyperkalemia is found, the easiest sort of reaction of any healthcare professional is to stop the RAASi. But that isn't necessarily the best way of managing it because these drugs are really helping in heart failure or in CKD. So we're thinking about in this situation of hyperkalemia why the problem has occurred, and that what the best treatment. So there might be a pause in RAASi, but it isn't stopping it. Often the hyperkalemia isn't real, which we've talked about before, and often there are other reversible factors. And if you thought about those, of course, then there's the newer potassium binders, which are really effective. And in this sort of circumstance where we want to continue RAASi's because of heart failure, because of chronic kidney disease, they can be really, really useful.

Andrew 
That's absolutely right. And the bottom line is that the RAASi, the ACE inhibitors and the angiotensin receptor blockers are powerfully protective for cardio renal disease, but only if we can get them inside the patient and not just in the packet. So the new potassium binders are generally safe. Well, I would say more than generally safe. They're safe medications that are really easy to use and they should be used more frequently to try and facilitate maximisation of RAASi, particularly in the context of high potassium. If a patient has their RAASi stopped, it should be made absolutely clear to them why they were stopped, what the problem was, and there should be a very clear plan considered of how to get the patient back on to their medicine at the right dose.

I'm going to point out to a resource. So CaReMe UK is an alliance of the major cardiac, kidney and metabolic primary care and secondary care specialty societies. And it's hosted on the British Cardiovascular Society, the BCS website. On their education hub, there is now a set of educational resources or utilities that can help you navigate, from primary care and indeed from secondary care, the management of hyperkalemia as a barrier to maintaining maximal RAASi dose. We'll put that link into our show notes, but it's very easy to find on the BCS site. The utilities are straightforward one pages that define more clearly how to introduce and optimise RAASi, how to manage acute hyperkalemia, bearing in mind the need to reinstate RAASi for these patients,

So we have to do this, but how to communicate effectively between secondary and primary care, because that's where the problem usually is, information about monitoring, and advice on how to ensure the patient is appropriately informed and educated about these drugs. These resources are really simple and easy to use.

Jeremy Levy 
That's really helpful. And new to me, that was the British Cardiovascular Society website and the CaReMe UK advice and guidance. I'll go and look at that when we finish chatting. But then Andrew, what about patients who then rightly stop or pause their RAASIs when they have an intercurrent illness because they've listened to their GP, their practice nurse, or even this podcast. And some patients do listen to what is told them. So they've paused their RAASi because they've had a current illness of whatever sort of fever, diarrhoea, or vomiting.

Andrew 
Yeah, this does happen and it's part of sick day guidance. Think we've covered this before, but it's really worth repeating. Patients should be told not to stop, but to hold or omit a drug while they're unwell and then resume after a couple of days, up to a week if they are better again. If they're not better, they need to go and see their GP. But if they are better, they don't need to see the GP to ask permission to start again.

And there really is good evidence that those who resume ACE or ARBS, RAASIs after an acute illness have a lower mortality and cardiorenal morbidity than those who stop but don't resume. So disruption to the journey needs returning to the harmony of ongoing RAASi treatment.

Jeremy Levy 
That's poetic, the harmony of ongoing RAASi treatment, Andrew. You should have been an author. What are your takeaways?

Andrew 
So the first one, of course, very important, subscribe to our podcast series because much of what we have discussed has also been dealt with in some of our previous podcasts on RAASi and on hyperkalemia management. And we'll put those details in the show notes. Additionally, really be mindful about hyperkalemia at the point of starting these medications. Consider who is at greatest risk. and how you can minimise and mitigate the risk of hyperkalemia disrupting care. Ensure the patient is empowered and activated and understands why they're on RAASi and the benefits that they get from this and that that would disappear if they were no longer able to take these medicines at the appropriate dose. So they can act as their own advocates when attending other departments.

For primary care also, please do look at the utilities on the BCS website as this will help you manage the patient's journey as you prescribe them RAASi. And again, I know I'm going beyond my normal three.

But for any secondary care doctor listening in, it is important that they understand that RAASi being stopped during an admission requires you to ensure that at discharge and in communication with the GP, you give primary care a clear plan for the reintroduction of these life-saving medicines.

Jeremy Levy 
Andrew, that's great. So we've established a date. You can't count, but you are very poetic. That's fantastic. ⁓ If you're listening, dear listener, in real time, you're going to be hitting Christmas soon, so happy Christmas. If you're not listening in real time, and we don't care when you listen, we hope you've enjoyed this episode.

Andrew 
Yes, and of course please be careful to remind your patients that Christmas pudding has a lot of potassium in it, but otherwise have a very Merry Christmas from me.

Jeremy Levy 
Bye.