Comparison of the efficacy and safety of benzbromarone and febuxostat in gout and hyperuricemia: a systematic review and meta-analysis

OBJECTIVE

Urate-lowering therapy (ULT) is widely recognized as the primary treatment for hyperuricemia and gout. Xanthine oxidase inhibitors (XOI), particularly febuxostat, have gained popularity as a frontline approach. However, the divergent efficacy and safety between febuxostat and the traditional ULT drug, benzbromarone, remain poorly understood. This knowledge gap necessitates a comprehensive analysis and evidence update to guide drug selection for physicians and patients.

METHOD

We conducted a systematic analysis by extracting relevant clinical studies from four medical literature databases. Forest plots, funnel plots, sensitivity analysis, Egger's test, and subgroup analysis were utilized to compare relevant indicators.

RESULTS

The advantages and disadvantages of the two drugs were evaluated based on various indicators such as serum uric acid (SUA), triglyceride (TG), urinary uric acid (UUA), white blood cell count (WBC), total cholesterol (TC), blood urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), estimated glomerular filtration rate (eGFR), and serum creatinine (SC). Benzbromarone demonstrated better efficacy in rapidly reducing SUA levels and inhibiting inflammation for hyperuricemia and gout patients. Febuxostat was slightly less effective in lowering SUA, but there was no significant difference in its impact on liver and kidney function after long-term use.

CONCLUSION

This study highlights the superiority of benzbromarone in rapidly reducing SUA and inhibiting inflammation. Febuxostat shows comparable effects on liver and kidney function after long-term use. These findings provide valuable insights for clinicians and patients in drug selection. Key Points • Benzbromarone stands out as a highly effective treatment for hyperuricemia and gout, offering rapid reduction of serum uric acid levels and potent anti-inflammatory effects. • When it comes to long-term use, febuxostat demonstrates comparable effects on liver and kidney function. This provides reassurance for patients who require extended treatment duration. • Moreover, our study goes beyond previous research by presenting a more comprehensive and detailed analysis.

Inhibition of mucus secretion by niclosamide and benzbromarone in airways and intestine

The Ca2+ activated Cl- channel TMEM16A (anoctamin 1; ANO1) is expressed in secretory epithelial cells of airways and intestine. Previous studies provided evidence for a role of ANO1 in mucus secretion. In the present study we investigated the effects of the two ANO1-inhibitors niclosamide (Niclo) and benzbromarone (Benz) in vitro and in vivo in mouse models for cystic fibrosis (CF) and asthma. In human CF airway epithelial cells (CFBE), Ca2+ increase and activation of ANO1 by adenosine triphosphate (ATP) or ionomycin was strongly inhibited by 200 nM Niclo and 1 µM Benz. In asthmatic mice airway mucus secretion was inhibited by intratracheal instillation of Niclo or Benz. In homozygous F508del-cftr mice, intestinal mucus secretion and infiltration by CD45-positive cells was inhibited by intraperitoneal injection of Niclo (13 mg/kg/day for 7 days). In homozygous F508del-cftr rats intestinal mucus secretion was inhibited by oral application of Benz (5 mg/kg/day for 60 days). Taken together, well tolerated therapeutic concentrations of niclosamide and benzbromarone corresponding to plasma levels of treated patients, inhibit ANO1 and intracellular Ca2+ signals and may therefore be useful in inhibiting mucus hypersecretion and mucus obstruction in airways and intestine of patients suffering from asthma and CF, respectively.

Comparison of the efficacy of febuxostat vs. benzbromarone in the treatment of gout: a meta-analysis in Chinese gout patients

OBJECTIVE

Febuxostat and benzbromarone are two common drugs for the treatment of gout, but the clinical efficacy of these two drugs is controversial. This meta-analysis aimed to compare the efficacy of febuxostat and benzbromarone in the treatment of gout.

MATERIALS AND METHODS

PubMed, Embase, and the Cochrane Library were searched for articles related to febuxostat and benzbromarone in the treatment of gout from inception to January 7, 2023. Titles and abstracts were reviewed in accordance with predesigned inclusion and exclusion criteria, and data were extracted independently. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of the studies, and the continuous variables were expressed as the standard mean square error (SMD) by STATA 16 (Stata Corp., College Station, TX, USA). The sensitivity analysis was conducted by randomly removing a study, and the heterogeneity was analyzed by funnel plots and Egger's test.

RESULTS

According to the search strategy, a total of 1,043 publications were retrieved from the three aforementioned databases, of which 45 publications were excluded due to duplication. Fourteen studies remained after screening titles and abstracts, and a total of 7 studies met the inclusion criteria after a comprehensive evaluation of the 14 studies. Meta-analysis showed that the uric acid (UA)-reducing effect of febuxostat is better than that of benzbromarone, while febuxostat showed a better ability to improve the estimated glomerular filtration rate (eGFR) and reduce Cr and blood urea nitrogen (BUN). In terms of hepatotoxicity, benzbromarone was not as potent as febuxostat in increasing alanine transaminase (ALT) and aspartate transaminase (AST), suggesting that benzbromarone has less hepatotoxicity. Moreover, there was no significant difference in the effect on blood lipid levels between the two drugs.

CONCLUSIONS

The beneficial effect of febuxostat on renal function-related indexes such as the eGFR, Cr and BUN is significant, while benzbromarone is more effective in reducing UA and has relatively less hepatotoxicity. The specific efficacy of the two drugs needs to be confirmed by further research.

Uric acid-lowering therapy with benzbromarone in hypertension with asymptomatic hyperuricemia: a randomized study focusing left ventricular diastolic function

BACKGROUND

Both hypertension and hyperuricemia are closely associated with the morbidity and mortality of heart failure with preserved ejection fraction (HFpEF). However, there is limited evidence on the effect of uric acid-lowering therapy on left ventricular (LV) diastolic function in this population. In this randomized study, we prescribed benzbromarone, a uric acid-lowering drug, to those with hypertension and asymptomatic hyperuricemia to investigate its clinical benefits by evaluating LV diastolic function, incidence of HFpEF and hospitalization for heart failure and cardiovascular death.

METHODS

230 participants were randomly assigned into two groups: uric acid-lowering group (benzbromarone) and control groups (without uric acid-lowering drug). The primary endpoint was LV diastolic function evaluated by echocardiography. The secondary endpoint of composite endpoints is the combination of new-onset HFpEF, hospitalization for heart failure and cardiovascular death.

RESULTS

After a median of 23.5 months' follow-up (16-30 months), the primary endpoint reflected by E/e' in benzbromarone group reached a significant improvement when compared to control group (p <.001). Composite endpoints occurred in 11 patients of the control group while only 3 patients occurred in the benzbromarone group (p = .027). We also presented the favorable trend of freedom from the composite endpoints or new-onset HFpEF using Kaplan-Meier curve by log-rank test in benzbromarone group (p = .037 and p = .054).

CONCLUSIONS

Our study demonstrated the efficiency of benzbromarone in hypertensive patients with concomitant asymptomatic hyperuricemia, including the benefits on ameliorating LV diastolic dysfunction as well as improving composite endpoints.

Comparison of benzbromarone and allopurinol on the risk of chronic kidney disease in people with asymptomatic hyperuricemia

OBJECTIVE

The objective of the study was to compare the relative effects of benzbromarone and allopurinol on the risk of developing chronic kidney disease in persons with asymptomatic hyperuricemia.

METHODS

A retrospective cohort study was conducted to analyze a 2003-2015 national database including all claims data of 2 million beneficiaries in Taiwan. Asymptomatic hyperuricemia was defined as follows: persons using urate-lowering drugs who never developed gout flares. The benzbromarone group included persons ages 20-84 that had asymptomatic hyperuricemia and received benzbromarone alone. The allopurinol group included persons ages 20-84 that had asymptomatic hyperuricemia and received allopurinol alone. The maximum follow-up time was set as 5 years in this study. The main outcome was defined as follows: persons were newly diagnosed with chronic kidney disease. A Cox proportional hazards regression analysis was performed to test the association between variables and the risk of chronic kidney disease.

RESULTS

After propensity score matching, 9107 persons in the benzbromarone group and 4554 persons in the allopurinol group were eligible for the study. Approximately 71% of the study subjects were males. The mean age was 56 years old. The incidence rate of chronic kidney disease was lower in the benzbromarone group than in the allopurinol group (1.18 versus 1.99/per 100 person-years, incidence ratio = 0.60, and 95% confidence interval = 0.52-0.68).The Cox proportional hazards regression analysis disclosed that after adjusting for co-variables, there was a decreased risk of developing chronic kidney disease in the benzbromarone group as compared with the allopurinol group (hazard ratio = 0.59, 95% confidence interval = 0.52-0.67 and P<0.001).

CONCLUSIONS

The use of benzbromarone is associated with a lower hazard of developing chronic kidney disease as compared to allopurinol use among persons ages 20-84 with asymptomatic hyperuricemia. More studies are needed to confirm our findings.

Superiority of Low-Dose Benzbromarone to Low-Dose Febuxostat in a Prospective, Randomized Comparative Effectiveness Trial in Gout Patients With Renal Uric Acid Underexcretion

OBJECTIVE

The predominant mechanism driving hyperuricemia in gout is renal uric acid underexcretion; however, the standard urate-lowering therapy (ULT) recommendation is first-line xanthine oxidase inhibitor (XOI), irrespective of the cause of hyperuricemia. This comparative effectiveness clinical trial was undertaken to compare first-line nontitrated low-dose benzbromarone (LDBen) uricosuric therapy to XOI ULT with low-dose febuxostat (LDFeb) in gout patients with renal uric acid underexcretion.

METHODS

We conducted a prospective, randomized, single-center, open-label trial in men with gout and renal uric acid underexcretion (defined as fractional excretion of urate <5.5% and uric acid excretion ≤600 mg/day/1.73 m2 ). A total of 196 participants were randomly assigned to receive LDBen 25 mg daily or LDFeb 20 mg daily for 12 weeks. All participants received daily urine alkalization with oral sodium bicarbonate. The primary end point was the rate of achieving the serum urate target of <6 mg/dl.

RESULTS

More participants in the LDBen group achieved the serum urate target than those in the LDFeb group (61% compared to 32%, P < 0.001). Rates of adverse events, including gout flares and urolithiasis, did not differ between groups, with the exception of greater transaminase elevation in the LDFeb group (4% for LDBen compared to 15% for LDFeb, P = 0.008).

CONCLUSION

Compared to LDFeb, LDBen has superior urate-lowering efficacy and similar safety in treating relatively young and healthy patients with renal uric acid underexcretion-type gout.

Design, synthesis, and biological studies of dual URAT1 inhibitor and FXR agonist based on benzbromarone

With increased unhealthy dietary patterns and a sedentary lifestyle, the prevalence of hyperuricemia is growing rapidly, placing a tremendous burden on the public health system. Persistent hyperuricemia in extreme cases induces gout, gouty arthritis, and other metabolic diseases. Benzbromarone is a potent human urate transporter 1 (URAT1) inhibitor that is widely used as a uric acid-lowering drug. Recent studies indicated that benzbromarone can also activate farnesoid X receptor (FXR), whereas its agonistic activity on FXR is rather poor. Mounting evidence suggested that the etiology of gout is directly related to NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasomes, and FXR suppresses the expression of NLRP3 in various ways. Therefore, the dual URAT1 inhibitor and FXR agonist may exert synergistic effects on decreasing uric acid (UA) levels and inhibiting inflammation. To obtain a better dual URAT1 inhibitor and FXR agonist, we performed the structure-based drug design (SBDD) strategy to improve the FXR activation of benzbromarone by forming strong interactions with ARG331 in FXR binding pocket. All of these efforts lead to the identification of compound 4, which exerts better activity on FXR and uric acid-lowering effect than benzbromarone.

Therapeutic Strategies for the Treatment of Chronic Hyperuricemia: An Evidence-Based Update

This article aims to critically review the evidence on the available therapeutic strategies for the treatment of hyperuricemia. For this reason, several papers were reviewed. Xanthine oxidase inhibitors are the safest and most effective uric acid lowering drugs for the management of chronic hyperuricemia, while the efficacy of uricosuric agents is strongly modulated by pharmacogenetics. Emergent drugs (lesinurad, peglotidase) were found to be more effective for the acute management of refractory hyperuricemia, but their use is supported by a relatively small number of clinical trials so that further well-designed clinical research is needed to deepen their efficacy and safety profile.

Association of gout medications and risk of cataract: a population-based case-control study

BACKGROUND

The relationship between gout medication use and cataract development is controversial. Moreover, limited clinical studies have evaluated this relationship.

AIM

To assess the effects of colchicine, allopurinol and benzbromarone on the risk of cataract in patients with gout.

DESIGN

Population-based nested case-control study.

METHODS

We enrolled 7900 patients who had received a new diagnosis of cataract >3 years after gout diagnosis into the study group and 33 475 patients who did not receive a diagnosis of cataract into the control group by matching for age, sex and the year of gout diagnosis at a ratio of 1:1. We used World Health Organization's defined daily dose (DDD) as a measure to assess the dosage of colchicine, allopurinol and benzbromarone exposure. Logistic regression was used to estimate crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of cataract.

RESULTS

The risk of cataract significantly increased in patients who received colchicine at a cumulative DDD of ≥66.5 (OR = 1.17, 95% CI = 1.01-1.36, P = 0.041). In the age-stratified analysis, patients with gout aged >60 years had a higher risk of cataract (OR = 1.27, 95% CI = 1.06-1.53, P = 0.011) than did patients aged <60 years. Allopurinol and benzbromarone had no association with cataract.

CONCLUSIONS

In this population-based nested case-control study, we observed that colchicine use increased the risk of cataract in patients with gout, especially in those aged >60 years who received colchicine at a cumulative DDD of >66.5.

Clinical efficacy and safety of benzbromarone in elderly hypertensive patients with hyperuricemia

To analyze the efficacy and safety of benzbromarone in elderly hypertensive patients with hyperuricemia. Sixty-six elderly hypertensive patients with hyperuricemia admitted to Beijing Civil Aviation General Hospital from February 2017 to February 2018 were enrolled in the study. According to computer randomization method, they were divided into two groups: The control group and the treatment group and there were 33 cases in each group. The routine treatment was used in the control group. The conventional treatment combined with benzbromarone treatment was applied to the treatment group. The clinical efficacy, blood pressure, blood uric acid level, inflammatory factor level and adverse event rate were analyzed. Clinical efficacy of the treatment group was higher than that of the control group (P<0.05); blood pressure, blood uric acid level, and inflammatory factor level in the treatment group was better than that of the control group (P<0.05); the incidence of adverse events in the treatment group was lower than that of the control group (P<0.05). Elderly hypertensive patients with hyperuricemia treated with benzbromarone have a significant clinical effect, which has a positive effect on improving clinical symptoms and reducing the probability of adverse events and has a high clinical promotion value.

Monosodium Urate Contributes to Retinal Inflammation and Progression of Diabetic Retinopathy

We have investigated the contributing role of monosodium urate (MSU) to the pathological processes associated with the induction of diabetic retinopathy (DR). In human postmortem retinas and vitreous from donors with DR, we have found a significant increase in MSU levels that correlated with the presence of inflammatory markers and enhanced expression of xanthine oxidase. The same elevation in MSU levels was also detected in serum and vitreous of streptozotocin-induced diabetic rats (STZ-rats) analyzed at 8 weeks of hyperglycemia. Furthermore, treatments of STZ-rats with the hypouricemic drugs allopurinol (50 mg/kg) and benzbromarone (10 mg/kg) given every other day resulted in a significant decrease of retinal and plasma levels of inflammatory cytokines and adhesion factors, a marked reduction of hyperglycemia-induced retinal leukostasis, and restoration of retinal blood-barrier function. These results were associated with effects of the hypouricemic drugs on downregulating diabetes-induced levels of oxidative stress markers as well as expression of components of the NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome such as NLRP3, Toll-like receptor 4, and interleukin-1β. The outcomes of these studies support a contributing role of MSU in diabetes-induced retinal inflammation and suggest that asymptomatic hyperuricemia should be considered as a risk factor for DR induction and progression.

Benzbromarone as a possible cause of acute kidney injury in patients with urolithiasis: Two case reports

RATIONALE

Reports of acute kidney injury (AKI) associated with benzbromarone use in patients with hyperuricemia (HUA) are rare so far.

PATIENT CONCERNS

We describe 2 unique clinical patterns in which benzbromarone was a possible cause of AKI following self-medication for HUA. In case 1, a 45-year-old man developed AKI after taking 100 mg of benzbromarone. His serum creatinine (Scr) increased to 2.3 mg/dL on day 2 after benzbromarone administration. Ultrasound showed multiple small stones in both kidneys, and the 24-hour urine uric acid level was 3128 mg. In case 2, a 17-year-old male student presented with AKI after self-administration of 50 mg of benzbromarone. His Scr increased to 6.8 mg/dL on day 3 after benzbromarone administration. Ultrasound showed multiple stones in the left kidney.

DIAGNOSIS

Both patients underwent renal biopsy, with findings of acute tubular interstitial nephropathy in case 1 and acute tubular damage in case 2. Drug-induced AKI was considered.

INTERVENTIONS

Both cases were treated supportively with intravenous hydration only. In both patients, the Scr level recovered within 0.5 months and renal function was normal 3 months after discharge.

LESSONS

Oral benzbromarone is widely used in Asian counties to treat HUA and the adverse effects are mostly mild. However, clinicians should be alert for benzbromarone-induced AKI. Moreover, uricosuric drugs should only be used after exclusion of urolithiasis and other contraindications.

A retrospective analysis of medication prescription records for determining the levels of compliance and persistence to urate-lowering therapy for the treatment of gout and hyperuricemia in The Netherlands

Urate-lowering therapy (ULT) is a recommended life-long treatment for gout patients. However, despite these recommendations, recurrent gout attacks are commonly observed in clinical practice. The purpose of this study was to assess the levels of compliance and persistence to ULT in The Netherlands, in order to reflect on the current gout care delivered by health professionals. Anonymous prescription records were obtained from IQVIA's Dutch retrospective longitudinal prescription database, containing ULT dispensing data for allopurinol, febuxostat, and benzbromarone from November 2013 to July 2017. Compliance to ULT was determined by calculating the proportion of days covered (PDC) over 12 months. Persistence over 12 months was evaluated by determining the time to discontinuation, without surpassing a refill gap of > 30 days. Association of PDC and persistence with age, gender, and first prescriber were examined using beta regression- and cox-regression models, respectively. There were 45,654 patients who met the inclusion criteria. Overall, 51.7% of the patients had a ULT coverage of ≥ 80% of the days in 1 year (PDC ≥ 0.80), and 42.7% of the patients were still persistent after 1 year. Men, older patients, and patients whose first prescriber was a rheumatologist were more persistent and had a higher PDC. Our results show that medication adherence to ULT after 1 year is suboptimal, considering that current guidelines recommend ULT as a life-long treatment. Future studies addressing the reasons for treatment cessation and improving treatment adherence seem warranted.

Discovery and characterization of verinurad, a potent and specific inhibitor of URAT1 for the treatment of hyperuricemia and gout

Gout is caused by elevated serum urate levels, which can be treated using inhibitors of the uric acid transporter, URAT1. Here, we characterize verinurad (RDEA3170), which is currently under evaluation for gout therapy. Verinurad specifically inhibits URAT1 with a potency of 25 nM. High affinity inhibition of uric acid transport requires URAT1 residues Cys-32, Ser-35, Phe-365 and Ile-481. Unlike other available uricosuric agents, the requirement for Cys-32 is unique to verinurad. Two of these residues, Ser-35 and Phe-365, are also important for urate transport kinetics. A URAT1 binding assay using radiolabeled verinurad revealed that distinct URAT1 inhibitors benzbromarone, sulfinpyrazone and probenecid all inhibit verinurad binding via a competitive mechanism. However, mutations made within the predicted transporter substrate channel differentially altered the potency for individual URAT1 inhibitors. Overall, our results suggest that URAT1 inhibitors bind to a common site in the core of the transporter and sterically hinder the transit of uric acid through the substrate channel, albeit with vastly different potencies and with differential interactions with specific URAT1 amino acids.

Outcome of Treatment in Gouty Arthritis Patients: A Retrospective Study

BACKGROUND

Effective treatment in gouty arthritis can prevent joint and renal damage. Target serum uric acid levels of < 6 mg/dl and < 5 mg/dl are recommended in gouty arthritis and those with tophi, respectively.

OBJECTIVE

To evaluate: (i) whether patients achieved recommended serum uric acid target and assess influencing factors and (ii) renal function between patients who achieved and not achieved the goal.

MATERIAL AND METHOD

The medical records of gouty arthritis patients treated in outpatient department at Thammasat University Hospital between January 2013 and December 2013 were reviewed. Patients were divided into adequately (ATG) and inadequately treated groups (ITG) based on the ACR uric acid criteria after six months of treatment. Factors associated with inadequate treatment were explored and post treatment renal function compared between A and ITGs.

RESULTS

Of 139 patients, 46 (33%) achieved target serum uric acid concentrations. Alcoholic consumption was the significant factor influencing the outcome. 75.5% of patients were followed-up > 1 month for second evaluation of uric acid and most of them not receiving dosage up-titration even though not achieving the target. Both groups had similar alterations of renal function after treatment (p = 0.68).

CONCLUSION

Most patients failed to achieve recommended uric acid targets. Alcohol consumption was identified as a key risk factorfor a suboptimal outcome. The treat-to-target approach should be underlined. Other risk factors should be explored prospectively.

Uricosuric medications for chronic gout

BACKGROUND

Uricosuric agents have long been used in the treatment of gout but there is little evidence regarding their benefit and safety in this condition.

OBJECTIVES

To assess the benefits and harms of uricosuric medications in the treatment of chronic gout.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 4, 2013), Ovid MEDLINE and Ovid EMBASE for studies to the 13 May 2013. We also searched the World Health Organization Clinical Trials Registry, ClinicalTrials.gov and the 2011 to 2012 American College of Rheumatology and European League against Rheumatism abstracts. WE considered black box warnings and searched drug safety databases to identify and describe rare adverse events.

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) or quasi-randomised controlled trials (controlled clinical trials (CCTs)) that compared uricosuric medications (benzbromarone, probenecid or sulphinpyrazone) alone or in combination with another therapy (placebo or other active uric acid-lowering medication, or non-pharmacological treatment) in adults with chronic gout for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies for inclusion, extracted data and performed a risk of bias assessment. Main outcomes were frequency of acute gout attacks, serum urate normalisation, study participant withdrawal due to adverse events, total adverse events, pain reduction, function and tophus regression.

MAIN RESULTS

The search identified four RCTs and one CCT that evaluated the benefit and safety of uricosurics for gout. One study (65 participants) compared benzbromarone with allopurinol for a duration of four months; one compared benzbromarone with allopurinol (36 participants) for a duration of nine to 24 months; one study (62 participants) compared benzbromarone with probenecid for two months and one study (74 participants) compared benzbromarone with probenecid. One study (37 participants) compared allopurinol with probenecid. No study was completely free from bias.Low-quality evidence from one study (55 participants) comparing benzbromarone with allopurinol indicated uncertain effects in terms of frequency of acute gout attacks (4% with benzbromarone versus 0% with allopurinol; risk ratio (RR) 3.58, 95% confidence interval (CI) 0.15 to 84.13), while moderate-quality evidence from two studies (101 participants; treated for four to nine months) indicated similar proportions of participants achieving serum urate normalisation (73.9% with benzbromarone versus 60% with allopurinol; pooled RR 1.27, 95% CI 0.90 to 1.79). Low-quality evidence indicated uncertain differences in withdrawals due to adverse events (7.1% with benzbromarone versus 6.1% with allopurinol; pooled RR 1.25, 95% CI 0.28 to 5.62), and total adverse events (20% with benzbromarone versus 6.7% with allopurinol; RR 3.00, 95% CI 0.64 to 14.16). The study did not measure pain reduction, function and tophus regression.When comparing benzbromarone with probenecid, there was moderate-quality evidence based on one study (62 participants) that participants taking benzbromarone were more likely to achieve serum urate normalisation after two months (81.5% with benzbromarone versus 57.1% with probenecid; RR 1.43, 95% CI 1.02 to 2.00). This indicated that when compared with probenecid, five participants needed to be treated with benzbromarone in order to have one additional person achieve serum urate normalisation (number needed to treat for an additional beneficial outcome (NNTB) 5). However, the second study reported no difference in the absolute decrease in serum urate between these groups after 12 weeks. Low-quality evidence from two studies (129 participants) indicated uncertain differences between treatments in the frequency of acute gout attacks (6.3% with benzbromarone versus 10.6% with probenecid; pooled RR 0.73, 95% CI 0.09 to 5.83); fewer withdrawals due to adverse events with benzbromarone (2% with benzbromarone versus 17% with probenecid; pooled RR 0.15, 95% CI 0.03 to 0.79, NNTB 7) and fewer total adverse events (21% with benzbromarone versus 47% with probenecid; pooled RR 0.43, 95% CI 0.25 to 0.74; NNTB 4). The studies did not measure pain reduction, function and tophus regression.Low-quality evidence based on one small CCT (37 participants) indicated uncertainty around the difference in the incidence of acute gout attacks between probenecid and allopurinol after 18 to 20 months' treatment (53% with probenecid versus 55% with allopurinol; RR 0.96, 95% CI 0.53 to 1.75). The study did not measure or report the proportion achieving serum urate normalisation, pain reduction, function, tophus regression, withdrawal due to adverse events and total adverse events.

AUTHORS' CONCLUSIONS

There was moderate-quality evidence that there is probably no important difference between benzbromarone and allopurinol at achieving serum urate normalisation, but that benzbromarone is probably more successful than probenecid at achieving serum urate normalisation in people with gout. There is some uncertainty around the effect estimates, based on low-quality evidence from only one or two trials, on the number of acute gout attacks, the number of withdrawals due to adverse events or the total number of participants experiencing adverse events when comparing benzbromarone with allopurinol. However, when compared with probenecid, benzbromarone resulted in fewer withdrawals due to adverse events and fewer participants experiencing adverse events. Low-quality evidence from one small study indicated uncertain effects in the incidence of acute gout attacks when comparing probenecid with allopurinol therapy. We downgraded the evidence because of a possible risk of performance and other biases and imprecision.

Prevention of comorbidity and acute attack of gout by uric acid lowering therapy

The object of this study was to evaluate the effect of uric acid lowering therapy in reducing the new development of comorbidities and the frequency of acute attacks in gout patients. We retrospectively reviewed patients who were diagnosed to have gout with at least 3 yr of follow up. They were divided into 2 groups; 53 patients with mean serum uric acid level (sUA)<6 mg/dL and 147 patients with mean sUA≥6 mg/dL. Comorbidities of gout such as hypertension (HTN), type II diabetes mellitus (DM), chronic kidney disease, cardiovascular disease (CVD) and urolithiasis were compared in each group at baseline and at last follow-up visit. Frequency of acute gout attacks were also compared between the groups. During the mean follow up period of 7.6 yr, the yearly rate of acute attack and the new development of HTN, DM, CVD and urolithiasis was lower in the adequately treated group compared to the inadequately treated group. Tight control of uric acid decreases the incidence of acute gout attacks and comorbidities of gout such as HTN, DM, CVD and urolithiasis.

[Stage-based treatment of integrative medicine on the quality of life in patients with gout]

OBJECTIVE

To investigate the quality of life in patients with gout and their influencing factors, and to observe the effects of the intervention program of stage-based treatment of integrative medicine (IM).

METHODS

Totally 120 patients with acute attack of gout within 72 h were randomly assigned to the treatment group and the control group, 60 in each group. Patients in the treatment group were treated with Huzhang Tongfeng Granule (HTG), diclofenac sodium extended-release capsule and Jinhuang Ointment (JO) in the acute stage, and Yinlian Tongfeng Granule (YTG) and Benzbromarone Tablet (BT) in the intermission stage. Patients in the control group were treated with diclofenac sodium extended-release capsule in the acute stage, and BT in the intermission stage. All patients were treated for 12 weeks. The quality of life (QOL) before and after treatment was investigated by questionnaire.

RESULTS

Before treatment there were no statistical difference in the physiological function, psychological function, social function, health self-awareness and total score between the two groups (P > 0.05). After treatment the scores of the four aspects and the total score were significantly improved in the two groups (P < 0.01). And the improvement of the treatment group was better than that of the control group (P < 0.01). There was no statistical difference in the gender, age, marital status, educational level, QOL with or without associated disease between the two groups (P > 0.05). The QOL of patients with joint stiffness or deformity was less than that of those without joint stiffness or deformity (P < 0.01). The total QOL scores of the gout patients were obviously correlated with the course of diseases (r = -0.324, P < 0.01).

CONCLUSIONS

The QOL of patients with gout was correlated with the course of disease and joint stiffness or deformity. Stage-based treatment of IM could significantly improve the QOL of f out patients.

[Assessment on the clinical efficacy and safety of xiezhuo chubi recipe in treating hyperuricemia]

OBJECTIVE

To observe the clinical efficacy and safety of Xiezhuo Chubi Recipe (XCR) on hyperuricemic patients.

METHODS

99 patients with hyperuricemia were randomly assigned to the XCR group, the Benzbromarone group, and the blank control group. Patients in the XCR group took XCR, one dosage daily, twice per day. Patients in the Benzbromarone group took Benzbromarone Tablet (50 mg each tablet, once per day). Patients in the blank control group were not treated with any drug, but only with clinical observation. Twenty days consisted of one course of treatment. The laboratory data including uric acid, blood routines, urine routines, the liver function, and the renal function were statistically analyzed before and after treatment.

RESULTS

The blood uric acid decreased in the three groups after treatment (P<0.05). The total effective rate was 85.71% in the XCR group, 92.86% in the Benzbromarone group, and 23.33% in the blank control group. There was no statistical difference between the XCR group and the Benzbromarone group (P>0.0167). There was no significant difference in the safety indices such as blood routines, urine routines, liver functions, and renal functions of the XCR group between before and after treatment (P>0.05).

CONCLUSION

XCR could effectively reduce the uric acid level with higher safety.

Drug-induced eosinophilic pneumonia with pulmonary alveolar hemorrhage caused by benzbromarone

A 51-year-old man was admitted to our hospital with cough, hemosputum, dyspnea and chest pain. Chest high-resolution computed tomography (HRCT) revealed diffuse ground-glass opacities in both lungs with peripheral predominance. Bronchoalveolar lavage fluid was fresh-bloody and analysis indicated an increase in the eosinophil proportion. Benzbromarone-induced lymphocyte stimulation test was positive. Therefore, the patient was diagnosed as having drug-induced eosinophilic pneumonia with pulmonary alveolar hemorrhage caused by benzbromarone. After discontinuation of benzbromarone and administration of corticosteroids, chest HRCT images and respiratory manifestation improved. Here, we report this rare case of benzbromarone-induced eosinophilic pneumonia with pulmonary alveolar hemorrhage.

[Establishment of therapeutic goal and plan of gout and asymptomatic hyperuricemia]

Gout is a crystal deposition disease. European and Japanese guidelines of management for gout recommend that serum urate concentration should be maintained below 6.0 mg/dL to promote crystal dissolution leading to prevention of recurrent gouty attack. Although allopurinol is recommended to be an adequate drug for urate lowering therapy in all gouty patients by European guideline, it is desirable that allopurinol is indicated in patients with overproduction type and benzbromarone in patients with underexcretion type, recommended by Japanese guideline. Asymptomatic hyperuricemia dose not equate to gout. As there is no evidence to support treatment of isolated hyperuricemia with urate lowering therapy currently, it is difficult to establish lowering goal of serum urate level in patients with asymptomatic hyperuricemia. Advice regarding lifestyle and treatment of associated comorbidity should be preferred to urate lowering therapy. However, urate lowering therapy may be indicated in high risk patients with hyperuricemia who are suffered from hypertension, diabetes mellitus, ischemic heart disease and renal insufficiency.

Efficacy and tolerability of urate-lowering drugs in gout: a randomised controlled trial of benzbromarone versus probenecid after failure of allopurinol

OBJECTIVES

To investigate the efficacy and tolerability of allopurinol as the first-choice antihyperuricaemic treatment for gout, and compare the efficacy and tolerability of benzbromarone and probenecid as second-choice treatment.

METHODS

Prospective, multicentre, open-label, two-stage randomised controlled trial in gout patients with normal renal function. Enrolled patients were given 300 mg allopurinol for 2 months (stage 1). Those patients who could not tolerate allopurinol or who did not attain the target serum urate concentration (sUr) < or=0.30 mmol/l (5.0 mg/dl), which was defined as successful, were randomised to benzbromarone 200 mg/day or probenecid 2 g/day for another 2 months (stage 2).

RESULTS

96 patients were enrolled in stage 1. 82 patients (85%) were eligible for the analysis at the end of stage 1: there was a mean (SD) decrease in sUr concentration of 35 (11)% from baseline; 20 patients (24%) attained target sUr < or=0.30 mmol/l; and 9 patients (11%) stopped allopurinol because of adverse drug reactions. 62 patients were enrolled in stage 2. 27 patients received benzbromarone (3 patients not eligible for analysis) and 35 received probenecid (4 patients not eligible for analysis). Treatment with benzbromarone was successful in 22/24 patients (92%) and with probenecid in 20/31 patients (65%) (p = 0.03 compared with benzbromarone). Compared with baseline values, there was a mean (SD) decrease of sUr concentration of 64 (9)% with benzbromarone and 50 (7)% with probenecid (p<0.001).

CONCLUSION

This study showed that allopurinol 300 mg/day has a poor efficacy and tolerability profile when used to attain a biochemical predefined target level of sUr < or =0.30 mmol/l, following 2 months of treatment. In stage 2, benzbromarone 200 mg/day was more effective and better tolerated than probenecid 2 g/day.

Biochemical effectiveness of allopurinol and allopurinol-probenecid in previously benzbromarone-treated gout patients

In 2003, the uricosuric drug benzbromarone was withdrawn from the market. The first alternative drug of choice was the xanthine oxidase inhibitor allopurinol. The purpose was to (1) investigate the efficacy of allopurinol (standard dosage) compared with previous treatment with benzbromarone; and (2) investigate the combination therapy allopurinol-probenecid as an effective alternative treatment compared with previous benzbromarone treatment. A prospective, open study was carried out in a cohort of 51 gout patients who discontinued benzbromarone therapy because of market withdrawal. Patients were given 200-300 mg allopurinol (stage 1). When allopurinol failed to attain the target serum urate (sUr) levels Collapse

Key Words Collapse

MESH Headings

• Allopurinol/adverse effects
• Allopurinol/therapeutic use
• Benzbromarone/therapeutic use
• Dose-Response Relationship, Drug
• Drug Therapy, Combination
• Female
• Gout/drug therapy
• Humans
• Hyperuricemia/drug therapy
• Male
• Middle Aged
• Probenecid/therapeutic use
• Uric Acid/blood
• Uric Acid/urine
• Uricosuric Agents/adverse effects
• Uricosuric Agents/therapeutic use

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Grants Collapse

Affiliation(s)

Mattheus K Reinders Department of Clinical Pharmacy and Pharmacology, Medical Centre Leeuwarden, Henri Dunantweg 2, 8934 AD, Leeuwarden, The Netherlands.
Eric N van Roon
Pieternella M Houtman
Jacobus R B J Brouwers
Tim L Th A Jansen

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Time required for disappearance of urate crystals from synovial fluid after successful hypouricaemic treatment relates to the duration of gout

OBJECTIVES

To determine whether hypouricaemic treatment results in the disappearance of urate crystals from gouty joints and to define the time required.

METHODS

In 18 patients with monosodium urate (MSU) crystal proven gout, and after the initiation of successful serum uric acid (SUA)-lowering treatment, an arthrocentesis of the asymptomatic signal joint (11 knees, 7 first metatarsophalangeal joints) was performed every 3 months to obtain a synovial fluid (SF) sample. The sample was then analysed for the presence of MSU crystals, and the number of crystals/400x field was noted. SUA levels and the duration of gout were also noted.

RESULTS

MSU crystals disappeared from the SF of all 18 joints after reduction of SUA to normal levels. The time required for disappearance ranged from 3 to 33 months; disappearance time correlated with the duration of gout (r(s) = 0.71; p<0.01). The median number of MSU crystals in the SF samples before urate-lowering treatment was 7.5 (2.5-11) crystals/400x field, reducing to 3 (1-6.5) crystals/400x field (p<0.05) at 3 months. Crystal counts continued to decrease after 3 months.

CONCLUSIONS

In gout, reduction of SUA to normal levels results in disappearance of urate crystals from SF, requiring a longer time in those patients with gout of longer duration. This indicates that urate crystal deposition in joints is reversible. Normalisation of SUA levels results in a decrease in the concentration of MSU crystals in SF in the asymptomatic gouty joints. This may partially explain the reduced frequency of gouty attacks when a patient has been treated with SUA-lowering drugs.

Excellent response to the clinical treatment of tophaceous gout

Gout continues to be a health problem around the world, and the treatment may turn into a real challenge when the patient presents a certain degree of chronic renal failure (CRF). We discuss a case of tophaceous gout in a 68-year-old male patient without urolithiasis and with uric acid (UA) underexcretion and CRF (creatinine clearance of 42 ml/min). Uricosuric treatment with benzbromarone and urinary alkalinization was administered, and acute gouty attacks improved substantially. Subsequently, allopurinol was added to the treatment to accelerate tophi reduction in the hands, feet, elbows and knees. After 30 months of treatment, serum UA declined from 10 to 3.2 mg/dl. Urinary UA excretion of 0.44 g/24 h in the baseline rose to 0.85 g/24 h, returning to the baseline value after 30 months. UA clearance tripled, rising from 3.05 ml/min before treatment to 9.48 ml/min, and remained at this level. It is worth stressing that even in cases of severe tophaceous gout, the response to clinical treatment may be satisfactory with substantial reduction of tophi and full acute gouty attack remission even in patients presenting a certain degree of CRF.

Benzbromarone therapy in management of refractory gout

AIM

To assess the efficacy and safety of benzbromarone in patients with renal impairment and severe tophaceous gout (despite receiving optimal conventional therapy).

METHODS

Six patients with refractory gout (despite optimal therapy) were treated with benzbromarone. Uric acid levels and number of gout attacks were recorded monthly. Adverse events to medications were also recorded.

RESULTS

After 1 year of treatment with benzbromarone, average uric acid level reduced from 0.61 mmol/L to 0.46 mmol/L. Repeated measures tests on the changes in uric acid were clinically significant (p=0.01). The frequency of acute attacks of gout was reduced from 16 (8-20) to 7.3 (1-16); p=0.01. None of the patients reported adverse events with the medications. There were no acute flares resulting from initiation of medications.

CONCLUSION

Benzbromarone is effective in lowering uric acid levels and in reducing the number of acute attacks of gout in patients who have failed optimal treatment. Making this drug more readily available will increase our therapeutic choices for urate reduction and help decrease the morbidity associated with gout.

Effect of urate-lowering therapy on the velocity of size reduction of tophi in chronic gout

OBJECTIVE

The optimal serum urate levels necessary for elimination of tissue deposits of monosodium urate in patients with chronic gout is controversial. This observational, prospective study evaluates the relationship between serum urate levels during therapy and the velocity of reduction of tophi in patients with chronic tophaceous gout.

METHOD

Sixty-three patients with crystal-confirmed tophaceous gout were treated with allopurinol, benzbromarone, or combined therapy to achieve serum uric acid levels less than the threshold for saturation of urate in tissues. The tophi targeted for evaluation during followup were the largest in diameter found during physical examination.

RESULTS

Patients taking benzbromarone alone or combined allopurinol and benzbromarone therapy achieved faster velocity of reduction of tophi than patients taking allopurinol alone. The velocity of tophi reduction was linearly related to the mean serum urate level during therapy. The lower the serum urate levels, the faster the velocity of tophi reduction.

CONCLUSION

Serum urate levels should be lowered enough to promote dissolution of urate deposits in patients with tophaceous gout. Allopurinol and benzbromarone are equally effective when optimal serum urate levels are achieved during therapy. Combined therapy may be useful in patients who do not show enough reduction in serum urate levels with single-drug therapy.

[Summary of the Dutch College of General Practitioners' "Gout" Standard]

The typical form of acute gout can be clinically diagnosed. The term 'complicated gout' is used if there are more than three acute attacks of gout per year, tophi or urate stones in the urinary tracts. In the case of recurrent probable acute gout, a diagnostic fine needle aspirate from the joint during an attack is indicated. First choice treatment of acute gout consists of NSAIDs. Colchicine is the second choice treatment and the third choice treatment consists of corticosteroids. Excessive alcohol use should be limited. Treatment of chronic gout depends on the uric acid excretion in the 24-hour urine. If the level of excretion is too low, the first choice should be benzbromarone, and if the uric acid output is too high, allopurinol should be the treatment of first choice. Increased fluid intake is recommended; maintenance treatment with colchicine is not advised. Consultation with or referral to a rheumatologist is indicated in the case of doubt about the diagnosis of 'acute gout' or 'complicated gout', or (suspected) bacterial arthritis and insufficient treatment effect.

Restoration of the uricosuric effect of probenecid after triglycylvasopressine administration in a gouty patient

A 35-year-old patient with severe gout and mild renal insufficiency presented very low urinary urate excretion. Volume expansion induced by fludrocortisone combined or not with a uricosuric drug (Benzbromarone) was unable to significantly increase his urate excretion. A combined Probenecid (PB) and Pyrazinamide (PZA) test was performed. These drugs being considered to affect renal tubular reabsorption or secretion. No significant modification of uric acid fractional excretion (FE.uric acid) was observed after PB and PZA. When the same test was performed after the administration of Triglycyl-lysine vasopressine (TGLV), a potent V1 receptor stimulator, we observed a three fold increase in FE.uric acid after PB intake (from 6 to 18%) followed by a decrease after PZA (from 18 to 5.6%). When TGLV was administered alone their was no significant modification of uric acid fractional excretion. We propose that TGLV decrease proximal tubular urate reabsorption that could only be detected when postsecretory reabsorption is blocked by an uricosuric drug.

Efficacy of allopurinol and benzbromarone for the control of hyperuricaemia. A pathogenic approach to the treatment of primary chronic gout

OBJECTIVES

To study the efficacy of allopurinol and benzbromarone to reduce serum urate concentrations in patients with primary chronic gout.

METHODS

Prospective, parallel, open study of 86 consecutive male patients with primary chronic gout. Forty nine patients (26 normal excretors and 23 under excretors) were given allopurinol 300 mg/day and 37 under excretors benzbromarone 100 mg/day. After achieving steady plasma urate concentrations with such doses, treatment was then adjusted to obtain optimal plasmatic urate concentrations (under 6 mg/dl).

RESULTS

Patients receiving allopurinol 300 mg/day showed a mean reduction of plasmatic urate of 2.75 mg/dl (from 8.60 to 5.85 mg/dl) and 3.34 mg/dl (from 9.10 to 5.76 mg/dl) in normal excretors and under excretors respectively. Patients receiving benzbromarone 100 mg/day achieved a reduction of plasmatic urate of 5.04 mg/dl (from 8.58 to 3.54 mg/dl). Fifty three per cent of patients receiving allopurinol and 100% receiving benzbromarone achieved optimal plasma urate concentrations at such doses. The patients with poor results with allopurinol 300 mg/day achieved a proper plasma urate concentration with allopurinol 450 to 600 mg/day, the mean final dose being 372 mg/day. Renal function improved and no case of renal lithiasis was observed among benzbromarone treated patients, whose mean final dose was 76 mg/day.

CONCLUSION

Benzbromarone is very effective to control plasma urate concentrations at doses ranging from 50 to 100 mg/day. Uricosuric treatment is a suitable approach to the treatment of patients with gout who show underexcretion of urate.

How should we treat tophaceous gout in patients with allopurinol hypersensitivity?

We studied purine metabolism in gouty patients from three categories: primary gout, familial juvenile hyperuricaemic nephropathy (FJHN) and partial HPRT deficiency.

Decreased serum concentrations of 1,25(OH)2-vitamin D3 in patients with gout

We measured serum concentrations of 1,25(OH)2-vitamin D3, 25(OH)-vitamin D3, parathyroid hormone (PTH), and uric acid in 114 male patients with primary gout and 51 normal male control subjects. Serum 1,25(OH)2-vitamin D3 was significantly lower in patients with gout compared with control subjects (38.4 +/- 11.9 v 44.4 +/- 11.0 pg/mL, P < .005), whereas no differences were observed between the two groups for serum 25(OH)-vitamin D3 or PTH. Serum uric acid was significantly higher in patients with gout versus control subjects (8.8 +/- 1.3 v 5.7 +/- 1.0 mg/dL, P < .0001). In addition, there was a significant negative correlation between serum uric acid and 1,25(OH)2-vitamin D3 concentrations (r = .17, P < .05). Administration of allopurinol or benzbromarone to the patients for 1 year caused a significant increase in serum 1,25(OH)2-vitamin D3, which was associated with a significant decrease in serum uric acid. In contrast, serum concentrations of 25(OH)-vitamin D3 and PTH were not affected by these drugs. These results suggest that uric acid per se may directly decrease serum 1,25(OH)2-vitamin D3 in patients with gout by inhibiting 1alpha-hydroxylase activity.