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Foundation years, you will have seen there uh in the BNF and when prescribing according to guidelines, there's a lot of information out there about EGFR creatinine clearance. Um These are not interchangeable and it can sometimes be confusing when to use one versus the other. So for most cases, most drugs, most people we can use eeg G Fr. But what's important to know is that EGFR is normalized to a body surface area of 1.73 m squared. So for people that have a body surface area that's really different from that, either either they're um very small or they have a, they are really overweight um or people who have different muscle mass, er extremes um such as the elderly people who are very frail amputees in those people, creatinine clearance can be better. Um and also in toxic drugs, creatinine clearance can be better. Um in people with ABM I of less than 18 or greater than 40 that's when you should be using your creatinine clearance. An ideal body weight should be used to calculate the creatinine clearance except if the patient's actual body weight is less than their ideal body weight. In which case, their actual body weight should be used. Now, there's an important point to mention here and that's about AK I. So in AK I, you should have caution when prescribing using either eeg fr or creatinine creatinine clearance. And really, you should not be prescribing according to either of those in AK I as you probably know, you should be stopping those nephrotoxic and that's not based on a specific number on the blood results that's based on as soon as you recognize that they have AK I stage 12 or three. That's when you should be stopping those nephrotoxic drugs. And it's the same. I'm thinking about prescribing analgesic agents. If the patient has an AK you should consider that and you should consider whether or not to prescribe those analgesic agents. And that's because creatinine in AK I lags behind. So what can happen is that as the ii instead of it representing the exact place that they're at in their pro in the progress of their AKI I or the recovery of their AKI I, it can, it can lag behind. So it might be that you've got blood results that are from yesterday or a few hours ago, the creatinine that you have from then will not be representative of what the patient's creatinine level is now. So as creatinine rises, so the AKI worsens, your eeg fr will overestimate your renal function and as creatinine falls and the kidney function improves your eeg fr will underestimate the renal function and creatinine clearance is inaccurate as well because the creatinine level is just rapidly changing in AK I. Whereas in CCK D using EEG Fr or creatinine clearance is much better because it's m much more of a stable or prolonged change. So it's not gonna change minute to minute, hour to hour, it's gonna change over months or years. So now we're gonna consider a little bit about prescribing analgesic agents in AK I. So first of all, thinking about nsaids and cox two inhibitors. So the way these work is they reduce prostaglandin synthesis, prostaglandins, increase your renal blood flow. And so when you've got conditions associated with reduced circulating volume, such as in a prerenal AK I, you, you're gonna have, you're gonna have increased prostaglandins in a normal patient who an increased prostaglandins, which is then going to increase your circulating volume. However, when you, when you've got a patient who is prescribed an NSAID, that NSAID is gonna stop that prostaglandin production, which means that you're then not gonna get that increase in renal blood flow in response. And so therefore, it can actually cause worsening perfusion and can drop your glomerular function, you know glomerular filtration. Therefore, we do advise that in any patient in AK I, you should be avoiding the use of nsaids or cox two inhibitors, uh opioids, the issue is slightly different. So with opioids, as I mentioned earlier, it's more about those metabolites accumulating. Uh And as we said, metabolite accumulation leads to increased side effects. You've got things like sedation, confusion, respiratory depression, and there are some opioids that are worse than others. So, morphine, pethidine codeine, those are worse for your me metabolite accumulation and renal impairment. Um And therefore, you should be really careful about what opioids you're prescribing. If you are gonna prescribe an opioid, you, you want to be using ones that are less reason exclusive. So things like oxyCODONE or fentaNYL, you can consider um you also want to avoid modified release opioids and that's because modified release opioids stay in the body for much longer. So we know that a modified release drug might last for 12 hours in a patient with normal renal function, but that can be doubled or tripled or quadrupled in patients with reduced renal function. And so by the time you give the next dose of the modified release, actually they've not cleared their previous dose. And the other thing to consider is that we probably need to be reducing the dose of opioids. Now, traMADol, er, it does have some er, opioid effects but it also has er, it's also a serotonin and noradrenaline reuptake inhibitor, which is why I've just put it in a slightly separate category. And with traMADol, it's the drug that accumulates rather than its metabolites. Um So we would recommend to reduce the dose and again avoid modified release for the same reason. So, now let's move on to C KD and there's a bit more to consider for KD. So just a bit of a recap. Er, so C KD five stages, um with each stage, your renal function is going to be decreasing. And when your eg fr gets below 60 that's when your drug and metabolite clearance starts to be affected. Once it starts getting down to below 30 you've got significantly altered drug, a metabolite clearance. And so that is when you gotta be really careful about prescribing. So we'll start off with paracetamol, er, generally safe. One of the best ones to prescribe in C KD. Um There are some recommendations that the B NF advisors. So if you've got an eeg fr less than 30 the B NF advisors that if you're gonna be using an IV, you should extend the dosing interval. Um So paracetamol is mainly metabolized by the liver and it's excreted mainly in the form of its metabolites in the urine, but less than 5% of it is excreted as unchanged paracetamol. And that's why in most people with healthy kidneys, that's not gonna be an issue, but in people with impaired renal function, that paracetamol that's unchanged as well as some of the metabolites can build up a little bit more. Um And so we recommend that six hour dosing interval and if eeg fr is less than 10, then you can think about decreasing the dose and also extending the dosing interval to six or eight hours. Now, another point to consider when prescribing paracetamol is in patients with er significantly reduced renal function. You want to also be avoiding your dispersable and effervescent paracetamol tablets. And that's because ef effervescent and dispersible paracetamol tablets contain a high concentration of sodium and patients in D can accumulate sodium. So you don't want to exacerbate that. So, NSAID considerations. So we've already talked about the problems that nsaids can have. Nsaids can precipitate. AK is. So AK I are on C KD and patients in KD are at higher risk of AK I. Um and we want to be especially careful if there's any additional physiological stresses. So for s for stage one and stage two, when your eeg fr is greater than 60 you have normal drug considerations that being said, whilst you've got only whilst you've got pretty normal um excretion of the nsaids. Er You've got to consider the fact that people with C KD also often have a lot of comorbidities. Um and those comorbidities may also cause a contraindication to NSAID use. Um So there are lots of contraindications to NSAID use. Um And again, there's a lot more detail on that in our first talk of the series um which I would recommend you go back and watch. Er but it is important to bear in mind that even if you know it's not the renal function that's stopping you, there may be other things that are stopping you. So it's not always our ideal drug of choice. Uh Once in, in stage two, whilst it is usual drug considerations, you need to be carefully considering the use if there's other physiological stresses. So if you're, if you've got a patient who is um POSTOP or bleeding or dehydrated and they've already got D they, all those things are going to increase their risk of getting an AK I and so prescribing an NSAID on top of that just increases their risk. And so in those cases, you are, think it is worth thinking about whether or not it's worth prescribing. And if, if you're in doubt, it's probably best to avoid. Once you get down to uh an EGFR of 60 or less, then you want to be avoiding nsaids. Um It's just gonna precipitate a, it's gonna make a renal function worse and it's gonna cause you a whole lot more problems. So now thinking about opioids, so again, we've said there's no change in renal clearance when your EGFR is above 60 when your glomerular filtration rate gets below 60 that's when your metabolite and your drug can accumulate. And we'll talk in more detail in a second about the specifics of opioid prescribing in general. Like we've talked about you want to be avoiding your controlled released, um modified, released, er opioids for the same reason as we discussed earlier, they can accumulate much easier. So you want to be avoiding them avoiding opioids if possible. But if you are going to be prescribing them, definitely do it at a reduced dose. And once you're getting down to less than 50 you'll want to, you'll want to be extending your dose interval as well. Um, a lot of this information might be quite a lot. So I'll give you some resources at the end to refer to, um, for things like doses and, um, which opioids are best. Um, the renal drug handbook, I'll, I'll let you know now is a good reference to refer to for opioid prescribing. Um, the renal drug handbook has uh a lot. It's not just for opioids, it's, and for um, analgesic agents, it's actually got a lot of drugs. Um, and it talks about how to prescribe them in C KD and what uh what eg fr you should be thinking about changing them. Um So if you're in doubt, um that's a really good resource to refer to. Er, so we'll just think about specifics, er, of opioid considerations. So, as I've said, you've got this risk of getting increased metabolite build up which can cause dangerous side effects, sedation, respiratory depression. So, if you can avoid the use, do so, if that means prescribing regular paracetamol, we would always recommend that um, you've also got increased opioid effects and prolonged opioid effects if you are going to prescribe it, ensure naloxone is ready because these, because people with CKD are at much higher risk. Um And you know, if you start noticing that they are having respiratory depression or sedation, then naloxone can be life saving. So just some specific opioids, um oxyCODONE, as I've already mentioned is one of our better ones. So it has less metabolite accumulation. There's still a risk of increased and prolonged effects in C KD. Um but it's much better than morphine and then codeine er because it can still accumulate, the metabolites can still accumulate. It is worth halving the dose once your eg fr gets below 50 traMADol. Um So traMADol is excreted by the kidneys. Um and just a recommendation of starting with immediate release, 50 MGB D with a maximum of 200 mg per 24 hours. And for all of these doses, the advice basically is start with a low dose and go slow with increasing. So if something, if, if a patient is not responding, if if their pain is not responding to this and they've not suffered any side effects from it, then by all means consider slowly increasing the dose for opioids, but you definitely wanna be starting low. Er fentaNYL is also a slightly better one in terms of renal impairment, so it doesn't have active or toxic metabolites. Um And again, some recommendations, more information is available in the B NF and also in the renal drug handbook with regards to doses. So don't feel you have to memorize any of this. Now codeine is starting to go more towards our red light. Um codeine is converted to morphine and that's how it, that's how we get its analgesic effect. You can still consider the use, but you've got increased risk of drowsiness due to increased cerebral sensitivity in people with renal failure. And you've also got increased risk of the other side effects um from codeine things like constipation. Um and that can be really uh important to think about in people who are on peritoneal dialysis. Um In general, codeine, codeine and morphine are ones that you should be thinking about prescribing less than something like oxyCODONE. Um just because the side effects are worse and there's more renal excretion and morphine, again, more renal excretion. Um And again, these are starting doses. So if your G fr is less than 50 start 75% if it's less than 20 start, 50% if it's less than 10, start 25% of your dose. And you want to definitely be increasing your, your dosing intervals if your GFR is less than 10 as well. Um again, start low and go slow. So now thinking about your adjuvants, so, um we'll start off with thinking about pregabalin and gabapentin. Um So again, with a, with a G fr of greater than 60 have no change in your renal clearance of your drug and metabolites. And therefore you don't have to really think about the change. It's the usual drug considerations when prescribing gabapentin and pregabalin. And again, referring back to our first talk, um that gives you much more detail on the indications and contraindications of prescribing pregabalin and gabapentin. Um So pregabalin is 98% r excreted, unchanged, gabapentin is eliminated solely by renal excretion. And therefore, once you get below a G fr of 60 that's when you wanna be reducing your dose and titr it to the response. And again, you can refer to the renal drug handbook and to the BNF for exact doses of that. Now, amitriptyline is a little bit different. Um, so it undergoes extensive first pass metabolism and is demethylase in the liver and its metabolites are really excreted, er, and its metabolites are not toxic, so you can dose it in normal for all KD stages. Um That being said, you may think, well, I'll just prescribe amitriptyline for everyone with CKD, but there are actually a lot of um, things to consider when prescribing amitriptyline, um which I'm not going to go into a lot of detail on because it, again, it was covered in our first talk. Um er, but it has also quite a lot of hazardous in hazardous drug interactions. Um, so it's just important to think, yes, I might not need to change the dose, but actually is it indicated and what drug interactions are there? And are there any contraindications before prescribing it? So that brings us to our case. So, um Mr Jones is a 78 year old man who is day one POSTOP following an elective cholecystectomy with a background of KD stage four. So he's complaining of pain following the operation, but he's already had paracetamol regularly, which is not helping which of the following would be the best analgesic for Mr Jones. I'll just give you a minute to think about that and if you wanna just write your answer in the chart, Um And if you wanna add an explanation as well, that would be amazing. So I can see a lot of people are saying D um which is good. So I'll just go back to my sides. Um So yes, so D is uh the right answer. Um And the reason for that. So a Ibuprofen, Ibuprofen is an NSAID. Um As you've said, nsaids can precipitate AK I in someone with C KD stage four and it should be avoided. Um codeine is one of our worst analgesics. Um It, it, it's worse than prescribing something like oxyCODONE. Um But also this patient is day one POSTOP and codeine may not be enough for someone like that. You may need, need to go straight to your top step of the wh o pain ladder with a strong opioid. Um We've already talked about during this talk about modified release and how you should avoid those because it can cause prolonged build up. Um And um oxyCODONE is better than morphine and that's why D is correct. You've got your immediate release, oxyCODONE with your breakthrough, immediate release oxyCODONE. So our key learning points, nsaids just avoid in renal impairment. Um In AK I and C KD is the safest thing. Opioids. If you are gonna use, use with caution, start low, go slow and extend your dosing intervals, monitor for signs of opioid toxicity and uh your immediate release is safer than your modified release. And here are some resources for you to just refer back to. So the BNF prescribing in renal impairment um has a good um kind of overview of things that I've mentioned today. Um The renal drug handbook, I've talked about a few times. Um that's really good for er, prescribing all sorts of er, drugs in renal impairment. And then you've got um think kidneys an NHS England campaign and that's more thinking about prescribing in AK I as well as West Midlands palliative care, um prescribing in renal failure have quite a good uh things have quite good information on there to refer to. Um So it's worth uh kind of having a look there for more information. So as I said, it's all part of a series this, so um our next session will be in thinking about pain management in patients with deranged LFT S. That will be next month and we'll post a date online um followed by pain management in palliative care. And then thinking about chronic pain and non pharmacological pain pain methods and our final talk of the series will be pain management in the trauma patient. Um and all of those will be posted online. So we'll have dates and times for them. Um So does anyone have any questions so I can see someone there? So, Maria, thank you. So, what about nefopam in patients with deranged eer? Um I actually am not that familiar with Naam. Um I can have a look for, for you and get back to you. Um But I it's not something that I'm particularly familiar with, I'm afraid, does anyone have any other questions? Um What I'll do is I am gonna just put a feedback um A QR code on the screen for you. Um And if you wouldn't mind before leaving, um just going um just clicking on this feedback link and giving me some feedback um that would be really, really helpful. And in the meantime, I'll continue answering any questions. So I've just looked up nefopam for you, Maria. So um the B MF, the B NF says to use it in caution and to reduce the daily dose in end stage renal failure. So that's thinking about D stage five. That's really when you'd have to make your um the most difference. Um And in terms of um doses in pregabalin, I don't know the dose off the top of my head. Um But all these doses, there's um specific details in the renal drug handbook and that's where I would really recommend you. Um Having a look, it's really, really good for telling you what EGFR someone has and therefore what um what dose to prescribe. Um You know, it's, it is really difficult to memorize specific doses for all different eg fr s that there are, but that is a really good resource to refer to when you're on the wards and prescribing. Thank you everyone for joining any more questions and I'll wait around if not, feel free to head off. Thank you. Thank you, everyone. Ok. I'm just gonna stop sharing now. So if anyone hasn't um used this QR code for the feedback form, I'd be really, really grateful if you could just scan it. Give me it doesn't take very long. It's like a one minute feedback form. I'd be really, really grateful if you could just complete that. Um I'll just leave it up for one more minute and then I'll stop sharing. Um I can try and get you a link one second. Is anyone else struggling with the, with the QR code? I don't think I have access to a link. Um but I will keep working on it. Oh, I'm glad you managed. I was just, I was just trying to get the link up. Um Thank you. I'm glad you've managed to sort it right. Um I am going to end it there. Thank you very much everyone for coming.