Urate-lowering Therapy: Initial Assessments and Ongoing Monitoring (Nursing)

00:00 Before a patient is started on urate-lowering therapy, several baseline tests are recommended.

00:06 It's a serum uric acid level, renal function and liver function tests.

00:11 Now for a serum uric acid level, we want that as a baseline and that will help us track the treatment effectiveness.

00:18 Renal function, you're gonna look at the EGFR, the GFR and the creatinine because we want appropriate dosing and monitoring.

00:26 The liver function tests are especially important for allopurinol and fubexistat.

00:31 Now, this next testing we're gonna discuss before starting allopurinol is only meant for specific populations and I'd like to explain.

00:40 So HLA-B5801 testing is a very specific genetic test.

00:47 The purpose of this test is to identify patients who are at an increased risk for developing severe cutaneous adverse reaction.

00:56 We shorten that to SCAR.

00:59 They're at risk for developing SCAR when they take allopurinol, which you know is a medication we use commonly to treat gout and hyperuricemia.

01:07 Now, these severe reactions that are included in SCAR include Steven-Johnson syndrome and toxic epidural necrolysis, which can be life-threatening.

01:17 Although allopurinol-induced SCAR is relatively rare, maybe as low as 0.1 to 0.4% of users, the mortality rate can be high and as high as 25%.

01:29 Now, the symptoms you're going to be watching for include rash, eosinophilia, leukocytosis, fever, hepatitis, and progressive kidney failure.

01:37 Okay, humor me for just a minute because I wanna go further into this genetic testing.

01:42 I want you to understand how it works, who we use it with, and why it benefits us because the research supports that HLA-B5801 screening is useful, but there's some special things you need to consider.

01:57 Now it's useful across different ethnic populations, but the sensitivity varies.

02:02 Now it has an 80 to 100% sensitivity in Korean, Thai, and Han Chinese populations.

02:09 Compare that to 50 to 60% sensitivity in European and Japanese populations.

02:15 Now the experts would be, we consider one of the experts to be the American College of Rheumatology.

02:21 Here's their recommendations.

02:23 They conditionally recommend testing for HLA-B before starting allopurinol for individuals of Southeast Asian descent, like the groups that we just talked about, and for African Americans.

02:37 However, they conditionally recommend against universal testing for other ethnic or racial backgrounds.

02:44 But if a patient tests positive for HLA-B5801, either heterozygous or homozygous, allopurinol treatment is absolutely contraindicated, and you're going to need to find an alternative medication to be used.

02:58 So this could mean that about one in five patients that are appropriate for testing could need alternative medications like Fiboxystat, but remember, it can have its own risks, including increased cardiovascular mortality.

03:12 Now once therapy's initiated, let's look at the recommendations for ongoing monitoring.

03:16 In regards to serum uric acid levels, these need to be done on a regular schedule.

03:21 So check every two to four weeks after the initiation or after each dose change of the medication.

03:28 After that, once it's stable and you're at target levels, it can be checked every six months.

03:33 You also want to consider a baseline ECG for patients who have cardiac risk factors if you're considering Fiboxystat because of its cardiovascular risk profile.

03:42 Let's take a look at some additional testing.

03:44 Renal function should be done every three to six months.

03:47 Liver function also is every three to six months initially, and then annually if it's stable.

03:52 And then watch for signs of hypersensitivity reactions, particularly during the first eight weeks of therapy when the risk is the highest.

04:00 Each medication also has some specific monitoring needs.

04:03 For allopurinol, you want to do a CBC, liver enzymes, and renal function needs to be watched closely and be particularly vigilant looking for signs of a rash during the first few months.

04:15 For Fiboxystat, particular attention.

04:17 You want to pay really close attention to the liver function and cardiovascular symptoms.

04:21 Make sure you ask the patient if they've having any chest pain, if they'd notice any shortness of breath, or if they have any palpitations every time you are with them.

04:30 Now, for probenicid, you want to monitor the urinary output and watch for signs of kidney stones.

04:35 You want to make sure the patient is drinking two to three liters a day so we don't end up with those crystals in their urinary tract.

04:42 Peglotticase has a higher potential to trigger immune responses compared to conventional medications.

04:48 Remember, Peglotticase is a biologic medication.

04:52 It's a modified uricase enzyme.

04:55 Now let's talk about some of the pre-infusion monitoring requirements.

04:59 Before and after each Peglotticase treatment, a blood test has to be performed to check the patient's uric acid level.

05:06 Now, if the uric acid level rises above six, this is a warning sign that we're in trouble.

05:11 Now, why would that be a warning sign? Well, an increase in uric acid levels during Peglotticase treatment, this would suggest the patient is developing antibodies against the medication.

05:22 Now, these antibodies not only reduce the medication's effectiveness, which explains the rising uric acid levels, but it also significantly increases the risk of potentially serious infusion reactions.

05:34 So if uric acid levels exceed six, treatment should be discontinued immediately for patient safety.