Rhabdomyolysis associated with initiation of febuxostat therapy for hyperuricaemia in a patient with chronic kidney disease

Rhabdomyolysis Associated With Febuxostat in a Non-Chronic Kidney Disease (CKD) Patient: Diagnostic and Management Challenges

Rhabdomyolysis is a critical medical condition characterized by the rapid breakdown of muscle tissue, releasing substances such as myoglobin and creatine kinase into the bloodstream, potentially leading to acute kidney injury. The etiology includes trauma, exertion, genetic factors, infections, and adverse drug reactions. Febuxostat, a non-purine selective xanthine oxidase inhibitor used to manage hyperuricemia in gout patients, is typically well-tolerated but has been associated with rare instances of severe adverse reactions like rhabdomyolysis. This case report describes a case of a 73-year-old male who developed rhabdomyolysis shortly after initiating febuxostat for gout management. He presented with significant lower back pain and progressive leg weakness, initially suspected to be an exacerbation of his degenerative disk disease. Laboratory findings revealed alarmingly elevated creatine phosphokinase levels, and diagnostics excluded other potential etiologies. The patient's condition significantly improved following the cessation of febuxostat and initiation of supportive care, including high-dose intravenous corticosteroids and hydration. This case underscores the need for vigilance in monitoring for rhabdomyolysis in patients starting febuxostat, especially when presenting with unexplained muscle weakness or pain.

Urate-Lowering Drugs and Muscle Injury: A Systematic Review and Network Meta-Analysis

Several urate-lowering drugs have been linked to muscle injury. This study investigated the association of oral urate-lowering drugs with the risk of muscle injury by performing a network meta-analysis of randomized and non-randomized controlled trials. A systematic search of MEDLINE, via PubMed, the ClinicalTrials.gov website, and the Cochrane Central Register of Controlled Trials was conducted to identify relevant studies with a primary outcome of "all muscle injuries." A random-effects model was used to perform a frequentist network meta-analysis to estimate whether there was significant heterogeneity among the studies. In total, 32 studies including 28,327 participants with 2694 (9.5%) "all muscle injuries" were assessed, and the overall risk of bias was judged to be low to moderate. No statistically significant differences were found between placebo and 6 urate-lowering therapies: allopurinol (risk ratio, RR, 1.05; 95% confidence interval, 95%CI, 0.63-1.73), febuxostat (RR 1.10, 95%CI 0.71-1.70), lesinurad (RR 7.00, 95%CI 0.31-160.36), lesinurad concomitant with allopurinol (RR 0.85, 95%CI 0.34-2.11), lesinurad concomitant with febuxostat (RR 1.97, 95%CI 0.55-7.03), and topiroxostat (RR 0.99, 95%CI 0.37-2.65). The findings suggest that there is little need to consider the risk of muscle injury when using urate-lowering drugs in the clinical setting.

Association between use of febuxostat and muscle injury: A disproportionality analysis and meta-analysis of randomized controlled trials

AIMS

Several reports have suggested an association between febuxostat and muscle injury. The purpose of this study was to determine whether febuxostat increases the risk of muscle injury. This study included an analysis of the US Food and Drug Administration Adverse Event Reporting System (FAERS) database and a systematic review/meta-analysis of randomized controlled trials.

METHODS

First, evaluation of the FAERS data included a disproportionality analysis that compared patients with and without rhabdomyolysis according to whether they were receiving febuxostat or allopurinol. Second, a systematic review/meta-analysis was performed to assess the risk of rhabdomyolysis and muscle injury in patients who used febuxostat or allopurinol.

RESULTS

Analysis of the FAERS data revealed disproportionality for increasing rhabdomyolysis in patients who received febuxostat (reporting odds ratio 4.49, 95% confidence interval [CI] 3.72-5.38, P < .01) and allopurinol (reporting odds ratio 2.49, 95% CI 2.25-2.75, P < .01). Nineteen studies were eligible for inclusion in the systematic review/meta-analysis. Rhabdomyolysis was reported in only 1 study. The risk of any type of muscle damage was not significantly increased with febuxostat compared with placebo (risk ratio 0.92, 95% CI 0.73-1.17, P = .52, I²  = 0%; 8 studies including 2597 participants, high-certainty evidence) or allopurinol (risk ratio 1.03, 95% CI 0.94-1.11, P = .56, I²  = 0%; 9 studies including 17 644 participants, moderate-certainty evidence).

CONCLUSION

Febuxostat does not seem to affect the risk of muscle injury. However, the findings of this meta-analysis indicate a need for further high-quality observational studies with long-term follow-up.

Side Effects and Interactions of the Xanthine Oxidase Inhibitor Febuxostat

The paper addresses the safety of febuxostat and summarizes reports on side effects and interactions of febuxostat published by the cut-off date (last day of literature search) of 20 March 2018. Publications on side effects and the interactions of febuxostat were considered. Information concerning the occurrence of side effects and interactions in association with the treatment with febuxostat was collected and summarized in the review. The incidence of severe side effects was much less frequent than mild side effects (1.2–3.8% to 20.1–38.7%). The rate and range of febuxostat side effects are low at doses of up to 120 mg and only increase with a daily dose of over 120 mg. The publications reveal no age-dependent increase in side effects for febuxostat. In patients with impaired renal function, no increase in adverse events is described with a dose of up to 120 mg of febuxostat per day. Patients with impaired liver function had no elevated risk for severe side effects. A known allopurinol intolerance increases the risk of skin reactions during treatment with febuxostat by a factor of 3.6. No correlation between treatment with febuxostat and agranulocytosis has been confirmed. Possible interactions with very few medications (principally azathioprine) are known for febuxostat. Febuxostat is well tolerated and a modern and safe alternative to allopurinol therapy.

The clinical significance of technetium-99m methylene diphosphonate bone scintigraphy findings in patients with rhabdomyolysis

OBJECTIVE

This study evaluated the relationship between bone scintigraphy finding and clinical factors and assessed the prognostic value of bone scintigraphy finding in patients with rhabdomyolysis.

PATIENTS AND METHODS

We retrospectively enrolled 143 patients with rhabdomyolysis who had undergone bone scintigraphy. Bone scintigraphy was classified into three groups: no or equivocal soft tissue uptake, a localized uptake, and a diffuse uptake. The relationship of bone scintigraphy findings with clinical factors was evaluated. Multiple logistic regression analysis was performed to identify the risk factors for acute renal failure (ARF) and renal replacement therapy (RRT).

RESULTS

Of 143 patients, 52 (36.4%) experienced ARF and 12 (8.4%) required RRT. Among cases caused by exercise, 83.7% showed localized soft tissue uptake. Diffuse soft tissue uptake was only shown among the patients with rhabdomyolysis caused by drug and toxin. Patients with localized or diffuse soft tissue uptake had higher levels of serum creatine kinase, myoglobin, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase compared with patients with no or equivocal uptake (P<0.05). Multiple logistic regression analysis showed that age, female sex, and serum phosphate level were associated with a risk for ARF and only serum creatinine level was associated with a risk for RRT (P<0.05). Bone scintigraphy findings failed to show significance for predicting ARF and RRT (P>0.05).

CONCLUSION

Soft tissue uptake on bone scintigraphy in patients with rhabdomyolysis was related to etiologies and showed limited value for predicting ARF and RRT.

Risk of Febuxostat-Associated Myopathy in Patients with CKD

BACKGROUND AND OBJECTIVES

Febuxostat, a nonpurine xanthine oxidase inhibitor, is widely used to treat hyperuricemia. Although febuxostat-associated rhabdomyolysis was reported in some patients with CKD, the association between CKD and febuxostat-associated myopathy remains uncertain.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our retrospective cohort study included 1332 patients using febuxostat in Taipei Medical University-Wanfang Hospital from February of 2014 to January of 2016. The primary predictor was time-averaged eGFR as calculated by the equation proposed by the 2009 Chronic Kidney Disease Epidemiology Collaboration. The outcome was febuxostat-associated myopathy defined as elevated creatine kinase levels during febuxostat use that were not attributed to other muscular injuries.

RESULTS

The median duration of febuxostat use was 224 days (25th, 75th percentiles: 86, 441.5 days). Of 1332 study participants, 1222 (91.7%) had CKD; the median eGFR was 20.8 ml/min per 1.73 m2 (25th, 75th percentiles: 9.0, 35.4 ml/min per 1.73 m2). Forty-one of the participants had febuxostat-associated myopathy (3.2%). All patients with myopathy had CKD, and the incident rate was 0.013 (95% confidence interval, 0.01 to 0.02) events per 100 patient-days in patients with CKD. Of 41 patients with myopathy, 37 had myositis, and four had rhabdomyolysis. Myopathy resolved in 17 patients who withdrew from treatment and eight patients who continued febuxostat treatment. Among the evaluated predictors, multivariate analysis showed that only the lowest eGFR tertile was significantly associated with myopathy in febuxostat users. The odds ratio of the lowest eGFR tertile to the highest tertile was 4.21 (95% confidence interval, 1.7 to 10.43). This finding remained consistent among subgroups stratified by age, sex, diabetes status, coronary artery disease, and statin or fibrate use.

CONCLUSIONS

Patients with severely reduced eGFR had higher risk of myopathy with treatment of febuxostat. Regular monitoring of creatine kinase level is suggested for early detection of febuxostat-associated myopathy, particularly in patients with CKD.

Febuxostat-associated eosinophilic polymyositis in marginal zone lymphoma

Febuxostat is an orally administered selective inhibitor of xanthine oxidase approved for the treatment of gout and prevention of tumor lysis syndrome. It is a relatively safe medication. Hypersensitivity reactions associated with the use of febuxostat are quite rare with only one reported case of DRESS syndrome. Recently, two case reports of rhabdomyolysis following the initiation of febuxostat were published. We hereby present the first case of rhabdomyolysis with hypereosinophilia following the administration of febuxostat to a 50-year-old patient newly diagnosed with marginal zone lymphoma. Three weeks after the initiation of febuxostat for tumor lysis syndrome prophylaxis, the patient presented with generalized weakness, diffuse myalgia and low-grade fever. Initial studies showed creatinine kinase level of 4471, hypereosinophilia of 1900/mm³, and LDH of 2691. All infectious and autoimmune diseases were ruled out. TSH level was normal. Muscle biopsy showed myonecrosis in addition to an eosinophilic inflammatory infiltrate in the endomysium and perimysium. Discontinuation of febuxostat led to prompt symptom resolution and normalization of blood tests eight days later.

Hyperuricemia-Related Diseases and Xanthine Oxidoreductase (XOR) Inhibitors: An Overview

Uric acid is the final oxidation product of purine metabolism in humans. Xanthine oxidoreductase (XOR) catalyzes oxidative hydroxylation of hypoxanthine to xanthine to uric acid, accompanying the production of reactive oxygen species (ROS). Uric acid usually forms ions and salts known as urates and acid urates in serum. Clinically, overproduction or under-excretion of uric acid results in the elevated level of serum uric acid (SUA), termed hyperuricemia, which has long been established as the major etiologic factor in gout. Accordingly, urate-lowering drugs such as allopurinol, an XOR-inhibitor, are extensively used for the treatment of gout. In recent years, the prevalence of hyperuricemia has significantly increased and more clinical investigations have confirmed that hyperuricemia is an independent risk factor for cardiovascular disease, hypertension, diabetes, and many other diseases. Urate-lowering therapy may also play a critical role in the management of these diseases. However, current XOR-inhibitor drugs such as allopurinol and febuxostat may have significant adverse effects. Therefore, there has been great effort to develop new XOR-inhibitor drugs with less or no toxicity for the long-term treatment or prevention of these hyperuricemia-related diseases. In this review, we discuss the mechanism of uric acid homeostasis and alterations, updated prevalence, therapeutic outcomes, and molecular pathophysiology of hyperuricemia-related diseases. We also summarize current discoveries in the development of new XOR inhibitors.

Febuxostat-associated drug reaction with eosinophilia and systemic symptoms (DRESS)

WHAT IS KNOWN AND OBJECTIVE

Febuxostat is recommended as an alternative drug for gouty patients with a history of allopurinol hypersensitivity or carrying the HLA-B*5801 allele.

CASE SUMMARY

An 81-year-old man with the medical history of gout presented to our clinic with generalized rashes for 2 days. After taking febuxostat for 2 days, he developed generalized skin rash with high fever. Laboratory tests showed elevated liver enzymes and acute kidney injury.

WHAT IS KNOWN AND OBJECTIVE

This is the first identified case of febuxostat-associated DRESS. Febuxostat should be withdrawn immediately when DRESS is observed to avoid further serious complications.

Urate-lowering therapy: current options and future prospects for elderly patients with gout

Gout is increasingly seen in the elderly population, in large part due to physiological decline in renal function with age, and as a result of therapy for comorbidities, in particular the use of diuretic therapies for hypertension and congestive heart failure. Urate-lowering therapy (ULT) is the cornerstone of successful long-term gout management with the aim of achieving a sustained reduction in urate (<0.36 mmol/L, or lower [<0.30 mmol/L] in those with tophi). After decades during which there has been relatively little interest in developing new agents to treat gout, the last 5-10 years has seen a plethora of new agents with several now used in routine clinical practice. There has also been a renewed focus on the optimal use of established ULT, specifically allopurinol, which remains the first-line therapy for most patients. There is emerging data on its use in patients with renal impairment and better recognition of risk factors of the rare but potentially lethal allopurinol hypersensitivity syndrome (AHS). Febuxostat, a new xanthine oxidase inhibitor, is now established in everyday practice. Uricosuric agents may be indicated in certain patient groups, whilst a new class of recombinant uricases (pegloticase) given by intravenous infusion may achieve dramatic and rapid urate-lowering effects. Cost and other factors have thus far limited its use to the very severe cases. Furthermore, increased understanding of urate metabolism has led to the development of a number of drugs currently under clinical evaluation. Common therapeutic targets are the urate transporters in the kidney and alternative xanthine oxidase inhibition pathways. These advances bode well for the better management of gout and hyperuricaemia in our elderly patients.

Role of Community Pharmacies for the Detection of Potentially Inappropriate Xanthine Oxidase Inhibitor Prescriptions

Background

Xanthine oxidase (XO) inhibitors are largely the treatment of choice for gout, but allopurinol is often inappropriately used for asymptomatic hyperuricemia. There is little evidence that allopurinol is useful in preventing cardiovascular diseases and therapeutic decisions must the balance the expected benefit with the potential harm.

Objective

To investigate the appropriateness of XO inhibitor use in relation to evidence-based indications and examine the role of community pharmacies in the detection of inappropriate prescriptions of these drugs.

Methods

This is an observational study conducted in eight community pharmacies. Each pharmacist was asked to interview a sample of patients who had received prescriptions of XO inhibitors. Patients were asked to complete a structured minimum data set that collected information on drug indication, history of gout, and presence of cardiovascular diseases.

Results

The study sample included 74 patients receiving XO inhibitors. About one third of patients reported being treated for asymptomatic hyperuricemia and had never had a gout attack. About half of the patients treated for asymptomatic hyperuricemia had been receiving the drug treatment for more than 3 years. Four asymptomatic hyperuricemic patients received allopurinol to treat hypertension. Among the patients treated for asymptomatic hyperuricemia, there was a higher presence of diabetes mellitus, obesity, previous myocardial infarction, and heart failure than in patients treated for an appropriate indication.

Conclusions

Inappropriate use of XO inhibitors is principally related to the treatment of hyperuricemia in patients with cardiovascular diseases. Community pharmacists have a central role in pharmacovigilance, by contributing to the prevention and identification of potentially inappropriate drug prescriptions.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-015-0016-7) contains supplementary material, which is available to authorized users.