Effects of fibric acid derivatives on biliary lipid composition

Probable Rare Case of Cholecystitis After Exposure to Supratherapeutic Doses of Hydralazine

Objective: To report a rare case of cholecystitis in a patient who received supratherapeutic doses of hydralazine for 1 month. Case Summary: A 79-year-old woman was admitted with severe right upper quadrant abdominal pain. Three weeks prior, she suffered a similar episode and was told she had a buildup of sludge in her gall bladder. For the past month, she had inadvertently received 400 mg of hydralazine per day instead of 150 mg; she was also prescribed fenofibrate 145 mg daily. Her workup was remarkable only for a slightly elevated white blood cell count and gall bladder sludge and distention without common duct obstruction. She was diagnosed with cholecystitis and underwent a laporoscopic cholecystectomy within 72 hours of admission. She was subsequently discharged a day later with the corrected hydralazine dose, and she has not been readmitted to the hospital. Discussion: Hydralazine is a direct acting vasodilator that may also potentiate the effects of nitric oxide. Nitric oxide has been linked to decreased gall bladder motility in in vivo and in vitro studies. The Naranjo algorithm indicates that this is a probable adverse event of fenofibrate and of hydralazine; the Drug Interaction Probability Scale indicates that this case of cholecystitis was a possible result of the interaction between hydralazine and fenofibrate. Based on the time course of the patient’s medication use and symptoms, hydralazine is more likely to be the cause of her cholecystitis than her other medications. Conclusion: Clinicians should be aware that high doses of hydralazine may inhibit gall bladder motility and contribute to the buildup of bile sludge.

A reappraisal of the risks and benefits of treating to target with cholesterol lowering drugs

Atherosclerotic cardiovascular disease (CVD) is the number one cause of death globally, and lipid modification, particularly lowering of low density lipoprotein cholesterol (LDLc), is one of the cornerstones of prevention and treatment. However, even after lowering of LDLc to conventional goals, a sizeable number of patients continue to suffer cardiovascular events. More aggressive lowering of LDLc and optimization of other lipid parameters like triglycerides (TG) and high density lipoprotein cholesterol (HDLc) have been proposed as two potential strategies to address this residual risk. These strategies entail use of maximal doses of highly potent HMG CoA reductase inhibitors (statins) and combination therapy with other lipid modifying agents. Though statins in general are fairly well tolerated, adverse events like myopathy are dose related. There are further risks with combination therapy. In this article, we review the adverse effects of lipid modifying agents used alone and in combination and weigh these effects against the evidence demonstrating their efficacy in reducing cardiovascular events, cardiovascular mortality, and all cause mortality. For patients with established CVD, statins are the only group of drugs that have shown consistent reductions in hard outcomes. Though more aggressive lipid lowering with high dose potent statins can reduce rates of non fatal events and need for interventions, the incremental mortality benefits remain unclear, and their use is associated with a higher rate of drug related adverse effects. Myopathy and renal events have been a significant concern with the use of high potency statin drugs, in particular simvastatin and rosuvastatin. For patients who have not reached target LDL levels or have residual lipid abnormalities on maximal doses of statins, the addition of other agents has not been shown to improve clinical outcomes and carries an increased risk of adverse events. The clinical benefits of drugs to raise HDLc remain unproven. In patients without known cardiovascular disease, there is conflicting evidence as to the benefits of aggressive pursuit of numerical lipid targets, particularly with respect to all cause mortality. Certainly, in statin intolerant patients, alternative agents with a low side effect profile are desirable. Bile acid sequestrants are an effective and safe choice for decreasing LDLc, and omega-3 fatty acids are safe agents to decrease TG. There remains an obvious need to design and carry out large scale studies to help determine which agents, when combined with statins, have the greatest benefit on cardiovascular disease with the least added risk. These studies should be designed to assess the impact on clinical outcomes rather than surrogate endpoints, and require a comprehensive assessment and reporting of safety outcomes.

Pharmacological effects of lipid-lowering drugs on circulating adipokines

The cardioprotective effects of lipid-lowering drugs have been primarily attributed to their effects on blood lipid metabolism. However, emerging evidence indicates that lipid-lowering drugs also modulate the synthesis and secretion of adipose tissue-secreted proteins referred to as adipokines. Adipokines influence energy homeostasis and metabolism and have also been shown to modulate the vascular inflammatory cascade. The purpose of this review will be to examine the reported effects of commonly used lipid-lowering drugs (statins, fibrates, niacin and omega-3-fatty acids) on the circulating concentrations of leptin, adiponectin, tumor necrosis-factor-α (TNF-α), Retinol binding protein 4 (RBP4) and resistin. Overall, the lipid-lowering drugs reviewed have minimal effects on leptin and resistin concentrations.Conversely, circulating adiponectin concentrations are consistently increased by each lipid-lowering drug reviewed with the greatest effects produced by niacin. Studies that have examined the effects of statins, niacin and omega-3-fatty acids on TNF-α demonstrate that these agents have little effect on circulating TNF-α concentrations. Niacin and fibrates appear to lower RBP4 but not resistin concentrations. The results of the available studies suggest that a strong relationship exists between pharmacological reductions in blood lipids and adiponectin that is not obvious for other adipokines reviewed.

Triglycerides and gallstone formation

Changes in bile acid (BA) metabolism and gallbladder function are critical factors in the pathogenesis of gallstones. Patients with hypertriglyceridemia (HTG) - often overweight and insulin resistant - are at risk for gallstone disease. The question arises whether HTG itself contributes to gallstone formation or whether gallstone disease only associates with this disorder. Triglycerides are formed in response to fluxes of non-esterified fatty acids and glucose. Hypertriglyceridemia results from either overproduction of triglycerides by the liver, impaired lipolysis or a combination of both. Hyperinsulinemia, as observed in the insulin resistant state, stimulates very low-density lipoprotein (VLDL)-triglyceride synthesis. Peroxisome proliferator-activated receptors (PPARs), liver X receptors (LXRs), farnesoid X receptor (FXR) and hepatocyte nuclear factor 4α (HNF4α) are the nuclear receptors involved in the regulation of lipogenesis. Microsomal triglyceride transfer protein (MTP) is involved in the production of VLDL and its activation is also under control of transcription factors as FXR and Forkhead box-O1 (FoxO1). Triglyceride and BA metabolism are linked. There is an inverse relationship between bile acid fluxes and pool size and VLDL production and SHP (small heterodimer partner) and FXR are the link between BAs and TG metabolism. BAs are also ligands for FXR and G-protein-coupled receptors, such as TGR5. FXR activation by BAs suppresses the expression of MTP, transcription factor sterol regulatory element binding protein (SREBP)-1c and other lipogenic genes. LXRs stimulate lipogenesis whereas FXRs inhibit the metabolic process. Synthesis of BAs from cholesterol occurs either via the classical pathway (7α-hydroxylation of cholesterol; CYP7A1) or via the alternate pathway (CYP39A1 or CYP7B1). BAs induce FXR, which inhibits CYP7A1 transcription by activation of SHP and inhibition of HNF4α transactivation. Bile composition (supersaturation with cholesterol), gallbladder dysmotility, inflammation, hypersecretion of mucin gel in the gallbladder and slow large intestinal motility and increased intestinal cholesterol absorption may contribute to the pathogenesis of cholesterol gallstones. In HTG patients supersaturated bile may be related to the presence of obesity rather than to HTG itself. Contraction and relaxation of the gallbladder are regulated by neuronal, hormonal and paracrine factors. Postprandial gallbladder emptying is regulated by cholecystokinin (CCK). Poor postprandial gallbladder contraction may be due to the magnitude of the CCK response and to the amount of CCK receptors in the gallbladder smooth muscle cells. In the fasting state gallbladder motility is associated with the intestinal migrating motor complex (MMC) activity and with elevated plasma motilin levels. Fibroblast growth factor (FGF19), produced on arrival of bile acids in the ileum, is also important for gallbladder motility. Gallbladder motility is impaired in HTG patients compared to BMI matched controls. There is evidence that the gallbladder in HTG is less sensitive to CCK and that this sensitivity improves after reversal of high serum TG levels by use of TG lowering agents. In hypertriglyceridemia TG lowering therapy (fibrates or fish-oil) is essential to prevent cardiovascular disease and pancreatitis. Fibrates, however, also increase the risk for cholelithiasis by increasing biliary cholesterol saturation and by reduction of bile acid synthesis. On the other hand fish-oil decreases biliary cholesterol saturation. Fish-oil may increase bile acid synthesis by activation of 7alpha-hydroxylase and may inhibit VLDL production and secretion through activation of nuclear factors and increased apoB degradation. In HTG patients, gallbladder motility improves during bezafibrate as well as during fish-oil therapy. The question remains whether improvement of gallbladder motility and increased lithogenicity of bile by bezafibrate therapy counteract each other or still result in gallstone formation in HTG patients.

Gemfibrozil-Induced Myositis in a Patient with Normal Renal Function

OBJECTIVE

To describe a case of gemfibrozil monotherapy-induced myositis in a patient with normal renal function

CASE SUMMARY

A 68-year-old white man presented to his primary care clinic complaining of a 6-month history of total body pain. His past medical history was significant for hypertension, diabetes mellitus, hyperlipidemia, gastroesophageal reflux disease, benign prostatic hypertrophy, arthritis, impotence, and pancreatic cancer that required excision of part of his pancreas. His home drug regimen included bupropion 75 mg twice daily, gemfibrozil 600 mg twice daily for the past 8 months, glimiperide 1 mg daily, insulin glargine 5 units at bedtime, insulin aspart 5 units in the evening, lisinopril 10 mg daily, omeprazole 40 mg daily, pregabalin 100 mg daily, and sildenafil 100 mg as needed. Laboratory test results were significant for elevated aspartate aminotransferase (AST) 78 U/L (reference range 15–46 U/L), alanine aminotransferase (ALT) 83 U/L (13–69 U/L), and creatine kinase (CK) 3495 U/L (55–170 U/L). Serum creatinine was normal at 1.19 mg/dL. The physician determined that the elevated CK indicated myositis secondary to gemfibrozil use, and gemfibrozil was subsequently discontinued. The patient returned 1 week later to repeat the laboratory tests. Results were CK 220 U/L, AST 26 U/L, ALT 43 U/L, and serum creatinine 1.28 mg/dL. The patient was asked to return in 3 weeks to repeat the laboratory tests. At that time, CK had continued to decrease to 142 U/L, and the AST and ALT had returned to normal, at 22 and 29 U/L, respectively. The patient reported complete resolution of total body pain 3 weeks after discontinuation of gemfibrozil. Follow-up 5 weeks after discontinuation revealed no change compared to the 3-week follow-up.

DISCUSSION

Myositis most often produces weakness and elevated CK levels more than 10 times the upper limit of normal. The risk of developing myositis, myopathy, or rhabdomyolysis is low (1%) when fibrates such as gemfibrozil are used as monotherapy. Evaluation of the literature revealed one case of gemfibrozilrelated myositis in a patient with chronic renal failure. There is also one report of myopathy associated with gemfibrozil monotherapy in a patient with normal renal function. The present case is the first documented case of gemfibrozil monotherapy-induced myositis in a patient with normal renal function. The Naranjo probability scale indicated a probable relationship between gemfibrozil treatment and the onset of myositis in our patient. Other potential causes of myositis were ruled out by patient interview and chart review.

CONCLUSIONS

Although the risk of myositis appears to be low with gemfibrozil monotherapy, clinicians should be aware of the potential for this adverse event. For patients taking gemfibrozil monotherapy who present with myalgia, discontinuation of the medication may be necessary for the alleviation of pain.

Treatment of hyperlipidaemia with fenofibrate and related fibrates

BACKGROUND

Fenofibrate is the most widely used fibrate. Its efficacy and tolerability in the treatment of hypertriglyceridaemia and combined hyperlipidaemia have been demonstrated in several clinical trials.

OBJECTIVE

To review the pharmacology, lipid-lowering and extra-lipid effects of fenofibrate and to preview ABT-335, an investigational new fenofibric acid molecule.

RESULTS

The effects of fenofibrate are mediated through the active metabolite fenofibric acid, and are described in detail in the paper. ABT-335 is a salt of fenofibric acid and, unlike fenofibrate, does not require first pass metabolism to the active moiety. ABT-335 is being developed for combination use with statins, and has recently completed three large Phase III randomised controlled trials in which the efficacy and safety of ABT-335 in combination with the three most commonly prescribed statins, atorvastatin, simvastatin and rosuvastatin, was evaluated in patients with mixed dyslipidaemia.

CONCLUSION

ABT-335 in combination with statins may provide a safe and efficacious treatment modality that enables achievement of several therapeutic goals in patients with mixed dyslipidaemia who have high cardiovascular risk.

Fish oil increases bile acid synthesis in male patients with hypertriglyceridemia

Fibrates are drugs of choice in patients with hypertriglyceridemia (HTG), but may increase the risk for gallstones by decreasing bile acid synthesis. Fish oil might be a therapeutic alternative, but its effect on bile acid metabolism in humans is unknown. We compared the effects of triglyceride-lowering therapy by fish oil or bezafibrate on cholesterol synthesis and bile acid metabolism in HTG. Cholesterol synthesis, bile acid pool sizes, and synthesis rates were compared between 9 male HTG patients and 10 normolipidemic controls matched for age, sex, and BMI. Effects of bezafibrate or fish oil were studied only in HTG patients in a randomized crossover trial. Patients had 14-fold higher serum triglyceride concentrations and greater cholesterol synthesis, as indicated by a 107% higher ratio of serum lathosterol to cholesterol (P < 0.01) than controls. The groups did not differ in bile acid metabolism. Both bezafibrate and fish oil reduced serum TG concentration (-68 and -51% vs. baseline, respectively). Compared with baseline, bezafibrate therapy was associated with reduced cholesterol synthesis (-25%, P = 0.009) without changes in bile acid synthesis rate and pool size. In contrast, fish oil increased bile acid synthesis (+31% vs. baseline, P = 0.07 and +53% vs. bezafibrate, P = 0.02) and altered bile acid distribution, as reflected by an increased ratio of the cholic acid (CA) synthesis rate to the chenodeoxycholic acid (CDCA) synthesis rate (+35% vs baseline, P = 0.05 and + 32% vs bezafibrate, P = 0.07) without effects on bile acid pool size or cholesterol synthesis. In conclusion, cholesterol synthesis is greater in HTG patients than in controls, whereas bile acid synthesis does not differ. Bezafibrate and fish oil have similar triglyceride-lowering capacities, but distinct effects on cholesterol synthesis. Bile acid synthesis is increased by fish oil, but not by bezafibrate therapy.

Fenofibrate: a novel formulation (Triglide) in the treatment of lipid disorders: a review

Cardiovascular disease is the major cause of mortality worldwide and accounts for approximately 40% of all deaths. Dyslipidemia is one of the primary causes of atherosclerosis and effective interventions to correct dyslipidemia should form an integral component of any strategy aimed at preventing cardiovascular disease. Fibrates have played a major role in the treatment of hyperlipidemia for more than two decades. Fenofibrate is one of the most commonly used fibrates worldwide. Since fenofibrate was first introduced in clinical practice, a major drawback has been its low bioavailability when taken under fasting conditions. Insoluble Drug Delivery-Microparticle fenofibrate is a new formulation that has an equivalent extent of absorption under fed or fasting conditions. In this review, we will discuss the clinical pharmacology of fenofibrate, with particular emphasis on this novel formulation, as well as its lipid-modulating and pleiotropic actions. We will also analyze the major trial that evaluated fibrates for primary and secondary prevention of cardiovascular disease, the safety and efficacy profile of fibrate-statin combination treatment, and the current recommendations regarding the use of fibrates in clinical practice.

Optimal management of hyperlipidemia in primary prevention of cardiovascular disease

Cardiovascular disease (CVD) in the developed countries continues to grow at an epidemic proportion. There are a significant number of young adults with no clinical evidence of CVD, but who have two or more risk factors that predispose them to CV events and death. Many of these risk factors are modifiable, and by controlling these factors, the CVD burden can be decreased significantly. Recent statistics have shown that, if all major forms of CVD were eliminated, the life expectancy would rise by almost 7 years. Hence it is imperative that primary prevention efforts should be initiated at a young age to avert decades of unattended risk factors. Hyperlipidemia has been linked to CVD almost a century ago. Since then various clinical trials have not only supported this link, but have also shown the CV benefits in aggressively treating patients with hyperlipidemia. In this generation, we have various therapeutic agents that are capable of reducing the elevated lipid levels. With drugs like statins, we are able to reduce the risk of CVD by about 30% and avoid major adverse events. Newer drugs are being researched and introduced in the treatment of hyperlipidemia in humans. These can be used in combination therapy resulting in optimal levels of lipids. The new National Cholesterol Education Program (NCEP)/Adult Treatment Panel III (ATP III) guidelines have come as a wake-up call to clinicians about primary prevention of CVD through strict lipid management and multifaceted risk management approach in the prevention of CVD.

Fibrates for treatment of the metabolic syndrome

The National Cholesterol Education Program Adult Treatment Panel III has provided a clinical definition for the metabolic syndrome that is practical for use in an office setting. Identification and treatment of the metabolic syndrome is of enormous public health importance because it is associated with a marked elevation in coronary heart disease risk and affects nearly 25% of adults in the United States. First-line therapy is lifestyle modification, which includes body weight reduction, increased physical activity, and moderation of the dietary glycemic load. Drug treatments focusing on the major components of the syndrome (atherogenic dyslipidemia, hypertension, and a prothrombotic state) have demonstrated efficacy for reducing coronary heart disease events. Fibrates seem to be particularly effective in patients for whom a disturbance of the triglyceride-high-density lipoprotein axis is the primary lipid disorder. Fibrates also appear to influence a number of emerging risk factors, including hemostatic and inflammatory markers and indicators of improved vascular wall biology, which may contribute to their cardioprotective effects.

Fenofibrate in the treatment of dyslipidemia: a review of the data as they relate to the new suprabioavailable tablet formulation

BACKGROUND

The fibric acid derivative fenofibrate is indicated as an adjunct to dietary modification in adults with primary hypercholesterolemia or mixed dyslipidemia (types IIa and IIb hyperlipidemia, Fredrickson classification) to reduce levels of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglycerides (TG), and apolipoprotein (apo) B, and to increase levels of high-density lipoprotein cholesterol (HDL-C) and apo A. It is also indicated as adjunctive therapy to diet for the treatment of hypertriglyceridemia (types IV and V hyperlipidemia). Initially approved in the United States in a micronized capsule formulation, fenofibrate is now available in a new "suprabioavailable" tablet formulation that has increased bioavailability, achieving equivalent plasma concentrations at lower doses. The 67- and 200-mg micronized capsules can be considered equivalent to the 54- and 160-mg suprabioavailable tablets, respectively.

OBJECTIVE

This paper reviews the pharmacologic properties, clinical usefulness, and safety profile of fenofibrate in the management of dyslipidemias.

METHODS

Recent studies, abstracts, reviews, and consensus statements published in the English-language literature were identified through searches of MEDLINE (1966-January 2002), International Pharmaceutical Abstracts (1970-January 2002), and PharmaProjects (1990-January 2002) using the search terms fenofibrate, fibrates, hyperlipidemia, hypertriglyceridemia, and dyslipidemia.

RESULTS

Fenofibrate is well absorbed after oral administration, with peak plasma levels attained in 6 to 8 hours. The absolute bioavailability of fenofibrate cannot be determined due to its being virtually insoluble in aqueous media suitable for injection; however, after oral administration of a single dose of radiolabeled fenofibrate, approximately 60% of the dose appeared in urine, primarily as fenofibric acid and its glucuronated conjugate, and approximately 25% was excreted in the feces. The apparent volume of distribution is 0.89 L/kg in healthy volunteers, and protein binding is approximately 99% in healthy and hyperlipidemic patients. Neither fenofibrate nor fenofibric acid appears to undergo significant oxidative metabolism in vivo. Fenofibric acid has a half-life of 20 hours. Fenofibrate is effective in lowering TG levels and increasing HDL-C levels. Its LDL-C-lowering effect is greater than that of gemfibrozil. Adverse effects of fenofibrate appear to be similar to those of other fibrates, including gastrointestinal symptoms, cholelithiasis, hepatitis, myositis, and rash. Fenofibrate therapy has been associated with increases in serum aminotransferase levels, and clinical monitoring of these markers of liver function should be performed regularly.

CONCLUSIONS

Fenofibrate is effective in reducing levels of TG, TC, and LDL-C, and increasing levels of HDL-C in patients with dyslipidemias. Its efficacy and tolerability in the treatment of hypertriglyceridemia and combined hyperlipidemia have been demonstrated in numerous clinical trials. Its use is accompanied by a low incidence of adverse effects and laboratory abnormalities. Fenofibrate protects against coronary heart disease not only through its effects on lipid parameters but also by producing alterations in LDL structure and, possibly, alterations in the various hemostatic parameters. Its uricosuric property may prove to be a useful adjunctive attribute.

Hypertriglyceridemia: associated risks and effect of drug treatment

Accumulating evidence indicates that hypertriglyceridemia (HTG) is a risk factor for cardiovascular disease. This increased risk is probably substantially mediated through the metabolic interrelationships between serum triglyceride (TG) levels and other risk factors, such as the atherogenic lipid profile (low high density lipoprotein-cholesterol levels and elevated small dense low density lipoprotein levels), insulin resistance, a prothrombotic propensity and low grade systemic inflammation. TG-lowering strategy in patients with HTG encompasses dietary modification and pharmacological agents, such as fibric acid derivatives, fish-oil and hydroxymethylglutaryl coenzyme A reductase inhibitors, which have, besides their known effects on the atherogenic lipid profile, beneficial effects on other determinants of cardiovascular disease. However, in spite of data from trials investigating fibric acid derivative-induced reduction in coronary events in patients with distinct types of hyperlipidemia, no specific trials have been performed that investigated this risk reduction in patients with HTG, in whom other cardiovascular risk factors are clustered as well. Small-scale studies on determinants of cardiovascular disease in patients with HTG and post-hoc analyses of the Helsinki Heart, Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial and Bezafibrate Infarction Prevention trials in patients with high serum TG levels suggest a drug-induced reduction in cardiovascular events. However, a specific trial should be conducted to investigate the effects of lipid-lowering therapy on clinical end-points in patients with HTG of defined types.

Micronized fenofibrate: a new fibric acid hypolipidemic agent

OBJECTIVE

To review the efficacy and safety of fenofibrate in the management of hyperlipidemias.

DATA SOURCES

A MEDLINE search (1974-October 1998), Current Contents search, additional references from article bibliographies, and the package insert from the manufacturer were used to identify data for evaluation. Studies evaluating fenofibrate (peer-reviewed publications, package insert data) were considered for inclusion. Abstracts and data on file with the manufacturer were not considered for inclusion.

STUDY SELECTION

English-language literature was reviewed to evaluate the pharmacology, pharmacokinetics, clinical use, and tolerability of fenofibrate. Data from animals and in vitro systems were included only when necessary to explain the drug's pharmacology.

DATA SYNTHESIS

Micronized fenofibrate is a fibric acid derivative approved by the Food and Drug Administration (FDA) in February 1998 for the treatment of types IV and V hyperlipidemia. Data from the peer-reviewed literature also support the use of fenofibrate in types IIa, IIb, and III hyperlipidemias. Micronized fenofibrate 67-201 mg/d is useful as monotherapy or as an adjunct to other hypolipidemics and dietary therapy. In placebo-controlled clinical trials, regular formulation fenofibrate 300-400 mg/d lowered serum triglyceride (TG) concentrations by 24-55%, total cholesterol by 9-25%, low-density lipoprotein cholesterol (LDL-C) concentrations by 6-35%, and raised high-density lipoprotein cholesterol (HDL-C) concentrations by 8-38%. Few comparative data exist regarding fenofibrate versus clofibrate and gemfibrozil. In noncomparative and comparative clinical trials, fenofibrate appeared to be well tolerated. The most common causally related adverse events were digestive, musculoskeletal, and dermatologic in nature. Concurrent use of fenofibrate and a hydroxymethylglutaryl-coenzyme A inhibitor may increase the risk of myopathy and/or rhabdomyolysis, although recent data suggest that concurrent use of fenofibrate with low-dose simvastatin or pravastatin is safe. Fenofibrate may enhance the effect of oral anticoagulants.

CONCLUSIONS

Fenofibrate reduces serum TG, total cholesterol, and LDL-C, and raises HDL-C to clinically relevant degrees. Its spectrum of activity appears to exceed that recommended for types IV and V hyperlipidemia to encompass types IIa, IIb, and III hyperlipidemias as well. To this extent, it may be considered a broader-spectrum fibrate than is indicated by its FDA approval. Adverse effects of fenofibrate appear to be similar to those of other fibrates and require routine monitoring (clinical, liver function). Long-term safety data are readily available from drug registries in many countries where the product has been available for nearly two decades. Cost-effectiveness studies comparing fenofibrate with other hypolipidemics demonstrate benefits of fenofibrate over simvastatin in types IIa and IIb hyperlipidemia. The need for dosage titration of the micronized preparation from 67 mg/d upward to a final dose of 200 mg/d is also not supported by peer-reviewed literature (except in the case of renal impairment). Although preliminary data on plaque regression are encouraging, published clinical studies evaluating the impact of fenofibrate on cardiovascular morbidity and mortality are awaited. Micronized fenofibrate is worthy of formulary inclusion.

Effects of different phenotypes of hyperlipoproteinemia and of treatment with fibric acid derivatives on the rates of cholesterol 7 alpha-hydroxylation in humans

Little is known about the relationships between hyperlipidemia and bile acid metabolism. However, hypolipidemic treatment with fibric acid derivatives has been shown to increase biliary cholesterol secretion, presumably by reducing bile acid synthesis. To clarify such relationships, we investigated the effects of different hyperlipoproteinemic conditions and of treatment with fibric acid derivatives on the rates of cholesterol 7 alpha-hydroxylation (the limiting step of bile acid synthesis) in humans. We studied 10 patients (aged 36 to 68 years) with lipoprotein phenotype IIa and with a clinical diagnosis of heterozygous familial hypercholesterolemia, a condition of reduced activity of LDL receptors, and 11 patients (aged 48 to 70 years) with lipoprotein phenotype IIb or IV and clinical diagnosis of familial combined hyperlipidemia, a condition probably related to increased hepatic lipoprotein synthesis. Cholesterol 7 alpha-hydroxylation rates were assayed in vivo by tritium release assay after an intravenous injection of [7 alpha-3H]cholesterol. The results were compared by ANOVA to the values obtained in a group of 28 normolipidemic patients (aged 34 to 83 years), with age as the covariate. Six patients were also studied after treatment with gemfibrozil (900 to 1200 mg/d for 6 to 8 weeks) and 5 patients were studied after treatment with bezafibrate (400 mg/d for 6 to 8 weeks). Hydroxylation rates were 0.82 +/- 0.22 mmol/d in the familial hypercholesterolemia group and 1.30 +/- 0.47 mmol/d in the familial combined hyperlipidemia group (P < .05 between the two groups and between patients with familial combined hyperlipidemia and control subjects; P = NS between patients with familial hypercholesterolemia and control subjects, as determined by ANOVA).(ABSTRACT TRUNCATED AT 250 WORDS)

Biliary lipids, lithogenic index and biliary drug concentrations during etofibrate and bezafibrate treatment

Hypolipidemic drugs like etofibrate and bezafibrate may induce lithogenic bile and increase the risk of gallstone formation. In this study, biliary lipids, lithogenic index and biliary drug concentrations were investigated in 6 hyperlipidemic patients after cholecystectomy. Patients were treated once daily for 5 days with either 500 mg/day etofibrate or 400 mg/day bezafibrate. Hepatic bile was collected for 6 days via T-drainage in 4 hourly aliquots. In the patients treated with etofibrate, the range of the lithogenic index remained stable with 0.89-1.69 before and 0.78-1.51 after 5 day drug therapy. In the bezafibrate group, the range of the lithogenic index rose from 0.81-1.40 to 1.26-1.66 mainly as a result of an increase of biliary cholesterol concentrations. Biliary drug concentrations were substantially higher under bezafibrate treatment than under etofibrate treatment. In conclusion, the fibrate drugs, etofibrate and bezafibrate, are different with regard to lithogenicity of bile and extent of biliary excretion. The safety profile of etofibrate may be preferably compared to other fibrate drugs.

The effect of simvastatin and bezafibrate on bile composition and gall-bladder emptying in female non-insulin-dependent diabetics

Female non-insulin-dependent diabetics have a high prevalence of gallstones. Treatment of hyperlipidaemia in these patients may modify the risk. Seventeen female non-insulin-dependent diabetics (age 35-65) were treated with simvastatin (n = 10) or bezafibrate (n = 7) and had the cholesterol saturation index (CSI) of bile and gall-bladder emptying measured before and after 3 months therapy. In both groups, there was a significant reduction in serum cholesterol following treatment. The mean pretreatment cholesterol saturation indices of bile did not differ between the two groups but, after 3 months therapy, there was a highly significant difference in CSI between the bezafibrate group (2.0 +/- 0.33) and the simvastatin group (1.1 +/- 0.14) P < 0.002. Whereas the increase in the CSI (42%) observed with bezafibrate therapy was significant, the decrease in the simvastatin group (14%) was only significant in those whose pretreatment cholesterol saturation indices were elevated. Despite the differences in CSI observed between the two treatment groups, no changes in gall-bladder emptying were detected.

Drug treatment of dyslipoproteinemia

This article has focused on the appropriate indications for lipid-lowering drugs in adult patients with different lipoprotein disorders, which we have divided into primary hypercholesterolemia, combined hyperlipidemia,and hypertriglyceridemia. The mechanism of action, efficacy, and safety profile of the major drugs have been reviewed, and based on this information, we have presented our views on the appropriate drugs of first choice and appropriate second-choice agents for treatment of adult patients with different dyslipidemias. The rationale for the use of hypolipidemic drugs is strongest in patients with hyperlipidemia who concurrently have evidence for coronary or peripheral vascular disease, in whom the goal of secondary prevention is to retard further progression of atherosclerosis and potentially induce some regression, whereas in selected high-risk patients without evidence of atherosclerosis, the goals of therapy are to prevent the premature development of CAD or, in patients with severe hypertriglyceridemia, prevent the adverse sequelae of hepatomegaly, splenomegaly, and potentially pancreatitis. We have focused on the use of hypolipidemic drugs in adult patients, and the guidelines discussed are not appropriate for use in children with hyperlipidemia, in whom drug therapy should be undertaken selectively and in consultation with a lipid specialist. Many areas of controversy in the use of lipid-lowering drugs remain to be addressed by future studies; these include the use of lipid-lowering drugs in patients with secondary causes of hyperlipidemia (e.g., the nephrotic syndrome), the use of lipid-lowering drugs in women, and recommendations for drug therapy in older patients.

Mode of action of fibrates

Fibrates are a class of hypolipidaemic drugs that effectively reduce plasma triglyceride and cholesterol levels, but also raise HDL cholesterol. In recent years the attention of pharmacologists and clinicians to fibrates has been renewed also in the light of a multifaceted action on plasma lipids as well as on factors modulating the thrombotic homeostasis in blood. The mechanisms of actions underlying these effects are discussed in this short review.

Double-blind comparison of bezafibrate versus placebo in male volunteers with hyperlipoproteinemia

The efficacy and safety of bezafibrate were evaluated in 83 patients with type IIa, IIb, or IV hyperlipoproteinemia. Following a 12- to 14-week placebo period on a coronary-prudent diet (Period 1), patients were assigned randomly to receive either bezafibrate 600 mg/day or placebo, plus diet in a double-blind, 12-week treatment period (Period 2). The return of lipid and lipoprotein levels toward baseline was evaluated in a subsequent 8-week period on placebo plus diet (Period 3). In patients with type IIa hyperlipoproteinemia, bezafibrate significantly lowered total (14.6%, P less than 0.001) and LDL-cholesterol (16.4%, P less than 0.001) and total (29.9%, P less than 0.001) and VLDL-triglyceride (44.0%, P less than 0.001) and significantly increased HDL cholesterol (9.5%, P less than 0.001). In patients with type IIb, bezafibrate had a qualitatively similar effect to that seen in type IIa on each of these lipoproteins, but the sample size was too small for statistical evaluation. In patients with type IV, bezafibrate lowered total (48.3%, P less than 0.01) and VLDL-triglyceride (57.7%, P less than 0.001) and VLDL-cholesterol (56.8%, P less than 0.001) and increased HDL-cholesterol (16.6%, P less than 0.05). All values returned toward baseline during Period 3. Only two bezafibrate patients experienced adverse events that were considered definitely treatment related; one was dropped from the study because of elevations in SGOT and SGPT, 1.5- and 4-times the upper limit of normal, respectively. For other laboratory parameters, trends upward or downward were small and of doubtful clinical significance. Bezafibrate appears to be effective and safe for modifying lipid and lipoprotein levels in patients with types IIa, IIb and IV hyperlipoproteinemia.

Effects of gemfibrozil and other fibric acid derivatives on blood lipids and lipoproteins

Fibric acid derivatives (FADs) are a class of drugs that have been shown to reduce the production of very low-density lipoprotein (VLDL) while enhancing VLDL clearance due to the stimulation of lipoprotein lipase activity. The drugs can reduce plasma triglyceride levels while raising high-density lipoprotein (HDL) cholesterol levels. Their effects on low-density lipoprotein (LDL) cholesterol levels are less marked and more variable. There is evidence that oral gemfibrozil (Lopid, Parke-Davis, Morris Plains, NJ) can reduce the risk of serious coronary events, specifically in those patients who had elevations of both LDL cholesterol levels and total plasma triglyceride levels with lower HDL cholesterol levels. Newer FADs (bezafibrate, ciprofibrate, fenofibrate) have been shown to have greater efficacy in reducing LDL cholesterol than gemfibrozil but, in general, these drugs are not as effective as the other primary drugs used to lower LDL levels. The FADs are also used to treat adult patients with very high levels of triglycerides who have pancreatitis and whose disease cannot be managed with dietary therapy. The FADs are well tolerated, with dyspepsia and abdominal pain the most common adverse effects. A small risk of cholelithiasis exists with these drugs, and caution should be used when combining these drugs with HMG-CoA reductase inhibitors because the combination increases the incidence of hyperlipidemic myositis and rhabdomyolysis.

Fenofibrate. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic use in dyslipidaemia

Fenofibrate is a lipid-regulating drug which is structurally related to other fibric acid derivatives, such as clofibrate. At the recommended dosage of 200 to 400 mg daily, it produces substantial reductions in plasma triglyceride levels in hypertriglyceridaemic patients and in plasma total cholesterol levels in hypercholesterolaemic patients. High density lipoprotein (HDL)-cholesterol levels are generally increased in patients with low pretreatment values. Fenofibrate appears to be equally effective in diabetic patients with hyperlipoproteinaemia without adversely affecting glycaemic control. The influence of fenofibrate on the plasma lipid profile is sustained during long term (2 to 7 years) treatment. Comparative studies conducted to date have involved only small groups of patients--in overall terms fenofibrate was at least as effective as other fibrates, but larger comparative studies are needed before valid conclusions on its relative efficacy compared with nonfibrate lipid-lowering drugs can be drawn. The influence of fenofibrate on morbidity and mortality from cardiovascular disease has not been studied. Clinical adverse reactions to fenofibrate have mainly consisted of gastrointestinal disturbances, headache and muscle cramps. Transient elevations in transaminase and creatine phosphokinase levels commonly occur. Isolated cases of hepatitis with substantially elevated transaminase levels have been reported. Fenofibrate induces hepatomegaly, peroxisome proliferation and hepatic carcinomas in rodents, but this type of hepatotoxicity has not been observed in humans. The biliary lithogenic index is increased by fenofibrate, but this has not been shown to have increased the incidence of gallstones in treated patients. Thus, fenofibrate offers an effective and well tolerated alternative to clofibrate or other fibric acid derivatives, but its relative efficacy and tolerability compared with other types of lipid-lowering drugs, and its effect on cardiovascular morbidity and mortality, remain to be clarified.

Treatment of hypercholesterolaemia with fenofibrate: a review

Hypercholesterolaemia is a metabolic disorder characterized by elevated total and LDL-cholesterol levels. Patients with hypercholesterolaemia are at high risk for coronary artery disease, and current guidelines recommend treatment for patients with elevated total or LDL-cholesterol levels. Fenofibrate is a fibric acid derivative that has been available in much of the world for over 10 years. In controlled and comparative clinical trials, fenofibrate has been shown to lower significantly plasma levels of total and LDL-cholesterol as well as plasma triglycerides. In addition, fenofibrate is associated with a relatively low incidence of adverse effects with some gastro-intestinal, dermatological and musculoskeletal reactions. Based on its efficacy and tolerability profile, fenofibrate would appear to be an appropriate choice for treatment of hypercholesterolaemia in selected patients.

Potential use of fenofibrate and other fibric acid derivatives in the clinic

The fibric acid derivatives continue to have a place in the treatment of hyperlipidemia. The third generation of these drugs, including fenofibrate, appears to offer some advantages over those currently available in the United States. These drugs should be prescribed only after dietary and lifestyle changes have been offered as the preferable treatment. In severe hypertriglyceridemia, clofibrate, gemfibrozil, or fenofibrate may reduce the very low-density lipoprotein and chylomicron levels adequately. Dysbetalipoproteinemia may also be completely controlled by a combination of diet and any one of these drugs. When the low-density lipoprotein level is elevated, the newer fibric acid derivatives, such as fenofibrate, may be more effective in lowering the plasma cholesterol levels. This is true for those patients with elevated low-density lipoprotein and normal very low-density lipoprotein triglyceride levels, as well as those with elevated very low-density lipoprotein triglyceride levels. A 20 percent reduction in low-density lipoprotein cholesterol levels is expected when the triglyceride levels are not elevated. When the very low-density lipoprotein triglyceride levels are elevated, the low-density lipoprotein response is more variable, and on occasion the low-density lipoprotein cholesterol level may rise as the very low-density lipoprotein level is reduced. The average reduction in low-density lipoprotein cholesterol levels (about 6 percent) caused by fenofibrate may be greater in patients with elevated very low-density lipoprotein triglyceride levels than by other fibrates. In combination with other agents that lower low-density lipoprotein levels more specifically, such as the bile acid sequestrants and hydroxymethylglutaryl coenzyme A reductase inhibitors, fenofibrate may act to effect control of the triglycerides allowing management of those patients with disorders producing elevated very low-density lipoprotein and low-density lipoprotein levels. Extensive European experience with fenofibrate (six million patient-years) indicates that severe side effects are unlikely. However, the physician should monitor patients for skin rash, liver and renal function abnormalities, gastrointestinal dysfunction, and generalized muscle tenderness. All of these usually appear very early in the course of treatment and are reversible. Of greater concern is the possibility of an increased incidence of cholelithiasis, since the bile becomes relatively enriched in cholesterol during therapy with any fibric acid derivative.(ABSTRACT TRUNCATED AT 400 WORDS)