Cell-specific toxicity of fibrates in human embryonal rhabdomyosarcoma cells

The effects of a variety of fibrates on the cell viability were examined in human embryonal rhabdomyosarcoma cells (HRMSC). Five fibrates, including fenofibrate, clofibrate, gemfibrozil, bezafibrate and ciprofibrate, all concentration-dependently reduced the cell viability determined by the mitochondrial enzyme activity. The cell injury occurred time-dependently and was marked at 24-48 h. The toxic action of fibrates was specific to HRMSC, since bezafibrate did not induce any marked changes in the viability of human microvascular endothelial cells or arterial smooth muscle cells. Synergistic cell injury was observed after a combined treatment with bezafibrate and simvastatin, although simvastatin alone reduced the cell viability. The cell injury was characterized by a typical nuclear damage, as evidenced by Hoechst 33342 staining and deoxynucleotidyl transferase dUTP nick-end label-positive staining. Similar cell-specific injury was induced by 8(S)-hydroxyeicosatetraenoic acid, a potent peroxisome proliferator-activated receptor alpha (PPARalpha) agonist. Consistent with these data, a marked expression for PPARalpha mRNA was observed in HRMSC but not in the endothelial or smooth muscle cells. Therefore, it is suggested that fibrates cause a cell-specific injury in HRMSC via activation of PPARalpha. Moreover, our present cell injury model using HRMSC may be useful for elucidating the mechanisms of clinical rhabdomyolysis induced by lipid-lowering agents.

Bezafibrate-induced anaphylactic shock: unusual clinical presentation

We report a case of a patient who suffered generalized urticaria, chest tightness, wheezing, nausea, vomiting, hypotension, and loss of consciousness. Two hours earlier she had taken Eulitop Retard following lunch. She had tolerated all the implicated food after the reaction. Allergy evaluation revealed intense positive responses to intradermal tests with bezafibrate active component and Eulitop Retard (skin tests in control subjects were negative). Specific IgE tests (RAST) to Eulitop Retard were negative. An IgE mechanism is suggested to be responsible for this adverse reaction on the basis of the positive skin tets. The delayed onset (two hours) of this anaphylactic shock is unusual. Although infrequent, it may be caused by the specific pharmacokinetic characteristics of this drug, which is a slow releasing agent, mainly absorbed in the gut. The drug was taken just after lunch, and this concomitant food ingestion could also have produced a delay in gastric drainage and a retarded drug absorption. An IgE-mediated accelerated type reaction could also explain this delay. Apparently the patient reacted after the first contact to the drug, and the absence of a sensitization period is not usual in this type of immune reponse. Finally, we recommend the performance of prick and intradermal skin tests prior to any systemic challenge when allergic reactions to fibric acid derivatives are suspected.

Rhabdomyolysis and acute renal failure following a switchover of therapy between two fibric acid derivatives

Drug induced myopathy has been reported with the use of fibric acid derivatives, hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and nicotinic acid. Over the last three decades, hypolipemiants like fibric acid derivatives and statins have been increasingly recognised as causes of rhabdomyolysis and acute renal failure especially during combination therapy and in the presence of underlying renal impairment. We report two cases of bezafibrate-induced rhabdomyolysis in patients with underlying coronary artery disease and pre-existing renal impairment. Both patients developed rhabdomyolysis leading to acute renal failure soon after their hyperlipidaemia treatment was changed from gemfibrozil to bezafibrate. There were no intercurrent illnesses or co-administration of other lipid lowering drugs in both patients. Even though both drugs belong to the same fibric acid derivatives group, these patients developed the complication only after a switchover of therapy.

Fibrate-induced increase in blood urea and creatinine: is gemfibrozil the only innocuous agent?

BACKGROUND

Some reports indicate that fibrates can induce renal dysfunction. However, the clinical characteristics of these episodes, and the respective nephrotoxicity of the four main fibrates used-namely, fenofibrate, bezafibrate, ciprofibrate, and gemfibrozil-remain ill defined.

METHODS

To better characterize this side-effect, we first reviewed the charts of 27 patients from our institution who developed an impairment of renal function during fibrate therapy. We next analysed the articles (n=24) that contained data on renal function in patients taking fibrates (n=2676).

RESULTS

Among our 27 patients, 25 were on fenofibrate therapy, one was taking bezafibrate, and one ciprofibrate. Nineteen were recipients of solid-organ transplants (kidney recipients, n=15; heart or heart-lung recipients, n=4), and eight were non-transplanted patients with some impairment of renal function. Baseline plasma creatinine ranged from 0.9 to 2.9 mg/dl. It increased by a mean of 40% after the start of fibrate therapy. There was a concomitant increase of blood urea values (mean 36%) in most of the patients. Renal function returned to baseline in 18/24 patients after fibrate discontinuation. However, six patients, all transplant recipients, experienced a permanent increase in plasma creatinine. The incidence of fibrate-induced renal dysfunction among our series of kidney transplant recipients was 60%, as it occurred in 15 of the 25 patients who had ever taken fibrates. An increase of mean creatinine values during therapy was described in all papers on fenofibrate (n=7) and bezafibrate (n=8) (range 8-18% and 8-40% respectively), and in three of four papers dealing with ciprofibrate (range 6-16%). No significant renal impairment was described in any of the eight articles reporting data on gemfibrozil therapy.

CONCLUSION

Therapy with fenofibrate, bezafibrate, and ciprofibrate may induce renal dysfunction. Gemfibrozil appears to be devoid of this side-effect.

A paradoxical severe decrease in serum HDL-cholesterol after treatment with a fibrate

There have been a handful of reports in the literature of a paradoxical decrease in serum high density lipoprotein (HDL)-cholesterol in patients on fibrate drugs. The reason for this decline in cardioprotective HDL-cholesterol is not known and may have potential deleterious effects on the patient. This report describes a decrease in serum HDL-cholesterol in a patient on both simvastatin and bezafibrate. This patient also developed abnormal renal function, probably interstitial nephritis. In addition, the literature of fibrate induced serum HDL-cholesterol decline is reviewed and possible mechanisms for this phenomenon discussed.

[Marked creatine-phosphokinase elevation in myopathy after treatment with bezafibrate]

Bezafibrate is a fibric acid derivative which has been widely used in the past 15 years. Recent studies have elucidated much of its mechanism of action, which mainly results in reduction of VLDL and triglyceride levels and in elevation of HDL. The drug is relatively safe and its side-effects well known, mild, and reversible. The most severe side-effect is myositis, varying from mild flu-like symptoms to rhabdomyolysis, which is extremely rare. The underlying situations most frequently associated with bezafibrate-induced myositis are renal insufficiency and concomitant treatment with certain other drugs. We describe 2 women who developed severe myositis with bezafibrate treatment. 1, aged 43, who had moderate diabetes but no renal insufficiency, was treated with metformin and warfarin, which can interact with bezafibrate and affect its metabolism. The other, aged 54, had renal insufficiency and was on home peritoneal dialysis. Her bezafibrate dose had been increased because of very high triglyceride levels. The aim of the study is to call attention to this significant side-effect of benzafibrate and to ways of preventing it.

Secondary prevention by raising HDL cholesterol and reducing triglycerides in patients with coronary artery disease

BACKGROUND

Coronary heart disease patients with low high-density lipoprotein cholesterol (HDL-C) levels, high triglyceride levels, or both are at an increased risk of cardiovascular events, but the clinical impact of raising HDL-C or decreasing triglycerides remains to be confirmed.

METHODS AND RESULTS

In a double-blind trial, 3090 patients with a previous myocardial infarction or stable angina, total cholesterol of 180 to 250 mg/dL, HDL-C < or =45 mg/dL, triglycerides < or =300 mg/dL, and low-density lipoprotein cholesterol < or =180 mg/dL were randomized to receive either 400 mg of bezafibrate per day or a placebo; they were followed for a mean of 6.2 years. The primary end point was fatal or nonfatal myocardial infarction or sudden death. Bezafibrate increased HDL-C by 18% and reduced triglycerides by 21%. The frequency of the primary end point was 13. 6% on bezafibrate versus 15.0% on placebo (P=0.26). After 6.2 years, the reduction in the cumulative probability of the primary end point was 7.3%, (P=0.24). In a post hoc analysis in the subgroup with high baseline triglycerides (> or =200 mg/dL), the reduction in the cumulative probability of the primary end point by bezafibrate was 39.5% (P=0.02). Total and noncardiac mortality rates were similar, and adverse events and cancer were equally distributed.

CONCLUSIONS

Bezafibrate was safe and effective in elevating HDL-C levels and lowering triglycerides. An overall trend in a reduction of the incidence of primary end points was observed. The reduction in the primary end point in patients with high baseline triglycerides (> or =200 mg/dL) requires further confirmation.

Acute renal failure after cardiopulmonary bypass: a possible association with drugs of the fibrate group

BACKGROUND

Renal failure is a recognized, but infrequent, complication following cardiac surgery. The causes for this condition are multifactorial, and a major concern is that the occurrence of postoperative acute renal failure is still associated with a high mortality rate.

METHODS AND MATERIALS

We report unexpected acute renal failure occurring in 4 patients after uncomplicated cardiac surgery. Each patient was taking a fibric acid derivative at the time of surgery. Renal failure occurred rapidly within 3 days of surgery and was associated with increased concentrations of skeletal muscle-derived creatine kinase (CK). One patient developed myoglobinuria, and another developed a malignant hyperthermia-like syndrome.

CONCLUSIONS

These cases show that patients receiving lipid lowering medications could be at higher risk of developing acute renal failure after cardiac surgery. This association merits careful evaluation in large prospective studies and, if proved, would suggest that patients taking either statins or fibrates should discontinue doing so before cardiac surgery.

Relapsing acute pancreatitis induced by re-exposure to the cholesterol lowering agent bezafibrate

We report a 75-yr-old patient, who presented three times with acute pancreatitis, accompanied by high temperature, shock, and multiorgan involvement and associated each time with exposure to the cholesterol lowering agent bezafibrate. Extensive workup excluded other possible causes for recurrent pancreatitis in this patient, further supporting bezafibrate as the cause of the patient's acute illness. Based on the short time elapsing between rechallenge and development of manifestations and the specific features of the attacks, we proposed hypersensitivity to bezafibrate as the underlying mechanism. The present report includes, for the first time, bezafibrate among definite causes of acute pancreatitis.

A comparison of the use, effectiveness and safety of bezafibrate, gemfibrozil and simvastatin in normal clinical practice using the New Zealand Intensive Medicines Monitoring Programme (IMMP)

AIMS

Because of the importance of treating dyslipidaemia in the prevention of ischaemic heart disease and because patient selection criteria and outcomes in clinical trials do not necessarily reflect what happens in normal clinical practice, we compared outcomes from bezafibrate, gemfibrozil and simvastatin therapy under conditions of normal use.

METHODS

A random sample of 200 patients was selected from the New Zealand Intensive Medicines Monitoring Programme's (IMMP) patient cohorts for each drug. Questionnaires sent to prescribers requested information on indications, risk factors for ischaemic heart disease, lipid profiles with changes during treatment and reasons for stopping therapy.

RESULTS

80% of prescribers replied and 83% of these contained useful information. The three groups were similar for age, sex and geographical region, but significantly more patients on bezafibrate had diabetes and/or hypertension than those on gemfibrozil or simvastatin. After treatment and taking the initial measure into account, the changes in serum lipid values were consistent with those generally observed, but with gemfibrozil being significantly less effective than expected. More patients (15.8%S) stopped gemfibrozil because of an inadequate response compared with bezafibrate (5.4%) and simvastatin (1.6%). Gemfibrozil treatment was also withdrawn significantly more frequently due to a possible adverse reaction compared with the other two drugs.

CONCLUSIONS

In normal clinical practice in New Zealand gemfibrozil appears less effective and more frequently causes adverse effects leading to withdrawal of treatment than either bezafibrate or simvastatin.

Results of the Bezafibrate Coronary Atherosclerosis Intervention Trial (BECAIT) and an update on trials now in progress

Bezafibrate is a latest generation fibrate derivative that substantially reduces total plasma cholesterol and triglyceride concentrations and increases high density lipoprotein (HDL) cholesterol. The Bezafibrate Coronary Atherosclerosis Intervention Trial (BECAIT) was a double-blind, placebo-controlled trial over 5 years to assess the angiographic benefits of bezafibrate retard (400 mg. day (-1) in young, male, post-myocardial infarction (post-MI) patients. The trial demonstrated that without lowering serum low density lipoprotein cholesterol, progression of coronary atherosclerosis was prevented and the coronary event rate reduced. In subgroup analyse, bezafibrate decreased the rate of progression of coronary atherosclerosis and coronary event rate in young post-MI patients, primarily by slowing the progression of mild-to-moderate lesions. Additional studies are underway to explore further the benefits of this fibrate in coronary heart disease. The Bezafibrate Infarction Prevention study is the first trial to investigate the effects of raising HDL cholesterol and lowering triglycerides in patients with established coronary disease. The Lower Extremity Arterial Disease Event Reduction study is assessing the benefit of lowering fibrinogen in the prevention of major ischaemic heart disease and stroke in patients with peripheral vascular disease.

Baseline characteristics of patients participating in the Bezafibrate Infarction Prevention (BIP) Study

Low high density lipoprotein (HDL) cholesterol, elevated triglycerides, or a combination of both, carries an increased risk of coronary heart disease (CHD). The benefit of therapy that increases serum HDL cholesterol concentrations and lowers triglyceride concentrations on the reduced incidence of myocardial infarctions and mortality has not been unequivocally demonstrated in healthy persons or patients with CHD. The Bezafibrate Infarction Prevention (BIP) study randomized men and women, with CHD and with total serum cholesterol 180 - 250 mg. dl-1, low density lipoprotein (LDL) cholesterol < or = 180 mg. dl-1 (< or = 160 mg. dl-1 below age 50 years), HDL cholesterol < or = 45mg. dl-1 and triglycerides < or = 300 mg. dl-1, to bezafibrate retard (400 mg once daily) or placebo. In addition to its effect on the lipids, this drug significantly lower plasma fibrinogen. The demographic, clinical and biochemical characteristics and existing cardiovascular therapy at baseline of 3122 patients randomized onto the study are presented here. A comparison is made with other on-going or recently published secondary prevention studies of lipid modification in CHD patients.

Efficacy and tolerance of 400 MG bezafibrate in diabetic and hyperlipidaemic patients

The authors report the results of an open clinical study using 400 mg Bezafibrate once a day. Among 25 diabetic patients (type II.) underwent a 4 weeks period with nutritional advice. Average changes from inclusion levels were -24% for total cholesterol, -56% for triglicerides, +11.9% for HDL-cholesterol, -19% for plama fibrinogen. In conclusion, bezafibrate at a daily dose of 400 mg had significant lipid-modifying properties but also exhibited a beneficial effect on other related risk factors such as fibrinogen reduction.

Warfarin potentiation with bezafibrate

Two cases are described in which lack of awareness of the potentiation of bezafibrate on warfarin was of clinical importance.

Comparison of bezafibrate and simvastatin in the treatment of dyslipidaemia in patients with NIDDM

Fibrates and HMG CoA reductase inhibitors are commonly used in the treatment of diabetic dyslipidaemia. However, these two groups of drugs have not been compared in diabetic patients in a randomized controlled trial. Therefore, a multicentre study was performed in 73 subjects with non-insulin-dependent (Type 2) diabetes mellitus (NIDDM) and combined hyperlipidaemia (serum cholesterol 6.2-10.0 mmol l(-1), serum triglycerides 2.3-10.0 mmol l(-1)), comparing the efficacy of 400 mg bezafibrate with 10 mg simvastatin in a double-blind fashion. Treatment with bezafibrate during 12 weeks reduced serum triglycerides significantly more than simvastatin (-41% vs -22%, p < 0.001) and increased HDL cholesterol more (bezafibrate: + 17% vs simvastatin: + 9%, p < 0.05). LDL cholesterol levels decreased by 14% (p < 0.001) during simvastatin and increased by 21% (p < 0.01) during bezafibrate. This increase in LDL cholesterol was positively correlated with fasting serum triglycerides (p < 0.001) and was associated with a reduction of the serum apolipoprotein B concentration, suggesting an increase in LDL particle size. Metabolic control of diabetes (fasting glycaemia; HbA1c) and insulin secretion (C-peptide levels) were unaffected by both treatments. The incidence of side-effects during treatment was similar for both drugs. Thus, 400 mg bezafibrate mainly increases HDL cholesterol and lowers serum triglycerides but at the expense of an increase in LDL cholesterol; 10 mg simvastatin lowers LDL cholesterin more effectively but has a smaller effect on HDL cholesterol and triglycerides.

Morphometry of abnormal peroxisomes induced by withdrawal of bezafibrate, a hypolipidemic drug in male rat hepatocytes

Peroxisomes containing fibrillar structures were induced after 1 week withdrawal of bezafibrate, a peroxisome proliferator. In this report, the relation between the duration of bezafibrate treatment and the induction of abnormal peroxisomes in rat hepatocytes was studied morphometrically. The abnormal peroxisomes did not appear during 3 to 90 days of treatment with bezafibrate, but they appeared after 1 week withdrawal of it. The number and frequency of abnormal peroxisomes were prominent in 3, 7, and 14 days of treatment followed by 1 week of withdrawal of bezafibrate. It was evident that the frequency of abnormal peroxisomes decreased with 30-90 days administration of bezafibrate. This means that long-term (30-90 days) treatment with bezafibrate suppresses the induction of abnormal peroxisomes.

Low total cholesterol is associated with high total mortality in patients with coronary heart disease. The Bezafibrate Infarction Prevention (BIP) Study Group

The present non-intervention screening study was undertaken to explore the relationships between pre-existing low total cholesterol and all-cause mortality. Eleven thousand, five hundred and sixty-three patients with coronary heart disease who attended a screening visit but were not included in the Bezafibrate Infarction Prevention study were followed-up for a mean of 3.3 years after determination of baseline total cholesterol. Five hundred and ninety-five (5%) of this largely unselected population who had total cholesterol levels < or = 160 mg.dl-1 formed the study population. The remaining 10968 patients acted as controls. The relative risk of all-cause mortality among patients with low cholesterol compared to others was 1.49 (95% CI: 1.16-1.91). The relative risk of non-cardiac death was 2.27 times higher in the low cholesterol group than in the controls (95% CI: 1.49-3.45), whereas the risk of cardiac death was the same in both groups (relative risk 1.09; 95% CI: 0.76-1.56). The most frequent cause of non-cardiac death associated with low total cholesterol was cancer. These results in patients with coronary heart disease add weight to previous studies associating low total cholesterol with an increased risk of non-cardiac death. However, a longer follow-up of this cohort of patients is necessary in order to clarify this association.