Retrospective population-based analysis of the dose-response (fecal fat excretion) relationship of orlistat in normal and obese volunteers

Dietary Sodium Suppresses Digestive Efficiency via the Renin-Angiotensin System

Dietary fats and sodium are both palatable and are hypothesized to synergistically contribute to ingestive behavior and thereby obesity. Contrary to this hypothesis, C57BL/6J mice fed a 45% high fat diet exhibited weight gain that was inhibited by increased dietary sodium content. This suppressive effect of dietary sodium upon weight gain was mediated specifically through a reduction in digestive efficiency, with no effects on food intake behavior, physical activity, or resting metabolism. Replacement of circulating angiotensin II levels reversed the effects of high dietary sodium to suppress digestive efficiency. While the AT₁ receptor antagonist losartan had no effect in mice fed low sodium, the AT₂ receptor antagonist PD-123,319 suppressed digestive efficiency. Correspondingly, genetic deletion of the AT₂ receptor in FVB/NCrl mice resulted in suppressed digestive efficiency even on a standard chow diet. Together these data underscore the importance of digestive efficiency in the pathogenesis of obesity, and implicate dietary sodium, the renin-angiotensin system, and the AT₂ receptor in the control of digestive efficiency regardless of mouse strain or macronutrient composition of the diet. These findings highlight the need for greater understanding of nutrient absorption control physiology, and prompt more uniform assessment of digestive efficiency in animal studies of energy balance.

Benefit-risk assessment of orlistat in the treatment of obesity

Orlistat, an inhibitor of intestinal lipase, has been available for the treatment of obesity for nearly two decades. In conjunction with a hypocaloric diet, orlistat treatment results in a placebo-subtracted reduction in body weight of around 3 kg at 1 year, and increases the likelihood of achieving clinically significant (≥5%) weight loss by around 20%. Orlistat-induced weight loss also confers modest improvements in systolic and diastolic blood pressure, low-density lipoprotein (LDL) cholesterol, glycemic parameters, and progression to diabetes in people with impaired glucose tolerance. Overall, it has a good safety profile, and serious adverse events (including reports of severe kidney and liver injury) are rare. However, a high rate of gastrointestinal side effects limits adherence to treatment.

Efficacy comparison of medications approved for chronic weight management

For the first time, patients who are obese are able to benefit from 5 different FDA approved pharmacologic agents for chronic weight management. Although weight loss from all of these medications was limited to 5% to 10% of total body weight loss in the Phase III clinical trials, patients are capable of losing more weight when a cumulative approach of diet, exercise, and multiple medications are used. A pilot study of adding phentermine to lorcaserin yielded double the weight loss than lorcaserin alone. A higher percentage of total body weight is lost with use of combination phentermine/topiramate compared to orlistat, lorcaserin, and bupropion/naltrexone but there are more contraindications to its use and potential cardiovascular adverse effects due to adrenergic agonism. Lorcaserin and bupropion/naltrexone yielded similar weight loss but carry different adverse effect profiles and interactions with other psychiatric medications may preclude use of one over the other. When choosing a medication for obesity, several factors need to be considered, such as comorbidities, medication interactions, and risk of potential adverse effects.

Effects of cactus fiber on the excretion of dietary fat in healthy subjects: a double blind, randomized, placebo-controlled, crossover clinical investigation

BACKGROUND

Cactus (Opuntia ficus-indica) fiber was shown to promote weight loss in a 3-month clinical investigation. As demonstrated by in vitro studies, cactus fiber binds to dietary fat and its use results in reduced absorption, which in turn leads to reduced energy absorption and ultimately the reduction of body weight.

OBJECTIVE

The objective of our study was to elucidate the dietary fat binding capacity of cactus fiber through determination of fecal fat excretion in healthy volunteers.

SUBJECTS AND METHODS

This clinical investigation was performed as a double-blind, randomized, placebo-controlled, crossover study in healthy subjects for a period of approximately 45 days. Twenty healthy volunteer subjects were randomized to receive cactus fiber or placebo, 2 tablets thrice daily with main meals. All subjects were provided with meals during the study period (except washout) according to a standardized meal plan, with 35% of daily energy need coming from fat. Two 24-hour feces samples were collected during both the baseline and treatment periods for analysis of the fat content.

RESULTS

Cactus fiber showed an increased fecal fat excretion compared with placebo (mean [SD] = 15.79% [5.79%] vs 4.56% [3.09%]; P < 0.001). No adverse events were reported throughout the study period.

CONCLUSIONS

Cactus fiber has been shown to significantly promote fecal fat excretion in healthy adults. The results of our study support the hypothesis that cactus fiber helps in reducing body weight by binding to dietary fat and increasing its excretion, thus reducing dietary fat available for absorption. ClinicalTrials.gov identifier: NCT01590667.

What are the pharmacotherapy options for treating prediabetes?

INTRODUCTION

The incidence of type 2 diabetes mellitus (T2DM) has risen to epidemic proportions, and this is associated with enormous cost. T2DM is preceded by 'prediabetes', and the diagnosis of impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) provides an opportunity for targeted intervention. Prediabetic subjects manifest both core defects characteristic of T2DM, that is, insulin resistance and β-cell dysfunction. Interventions which improve insulin sensitivity and/or preserve β-cell function are logical strategies to delay the conversion of IGT/IFG to T2DM or revert glucose tolerance to normal.

AREAS COVERED

The authors examine pharmacologic agents that have proven to decrease the conversion of IGT to T2DM and represent potential treatment options in prediabetes.

EXPERT OPINION

Weight loss improves whole body insulin sensitivity, preserves β-cell function and decreases progression of prediabetes to T2DM. In real life long-term weight loss is the exception and, even if successful, 40 - 50% of IGT individuals still progress to T2DM. Pharmacotherapy provides an alternative strategy to improve insulin sensitivity and preserve β-cell function. Thiazolidinediones (TZDs) are highly effective in T2DM prevention. Long-acting glucagon-like peptide-1 (GLP-1) analogs, because they augment β-cell function and promote weight loss, are effective in preventing IGT progression to T2DM. Metformin is considerably less effective than TZDs or GLP-1 analogs.

Obesity and the need for bariatric surgery in Pakistan

After establishing a foothold in the West, the pandemic of obesity now threatens to spin out of control in the developing nations of Asia and the Indian subcontinent. Like many of its neighbors, Pakistan has witnessed an unprecedented growth in the number of overweight and obese individuals in its population, and obesity is proving to be an issue of considerable public health concern. Conventional medical therapies for obesity and related complications have proven to be less than effective, especially in the population of the southeast, which appears to be inherently predisposed to developing obesity-related complications. Bariatric surgery is fast emerging as a definitive therapeutic alternative for obesity and has proven to be highly successful and cost-effective at producing remission of complications of the same. In this article, we expound the need for introducing and incorporating bariatric surgery as part of the therapeutic protocols for obese individuals of South Asian descent suffering from the chronic and debilitating complications of obesity.

The modulation of pancreatic lipase activity by alginates

Alginates are comprised of mannuronic (M) and guluronic acid (G) and have been shown to inhibit enzyme activity. Pancreatic lipase is important in dietary triacylglycerol breakdown; reducing pancreatic lipase activity would reduce triacylglycerol breakdown resulting in lower amounts being absorbed by the body. Lipase activity in the presence of biopolymers was assessed by enzymatic assay using natural and synthetic substrates. Alginate inhibited pancreatic lipase by a maximum of 72.2% (±4.1) with synthetic substrate (DGGR) and 58.0% (±9.7) with natural substrate. High-G alginates from Laminaria hyperborea seaweed inhibited pancreatic lipase to a significantly higher degree than High-M alginates from Lessonia nigrescens, showing that inhibition was related to alginate structure. High-G alginates are effective inhibitors of pancreatic lipase and are used in the food industry at low levels. They could be included at higher levels in foods without altering organoleptic qualities, potentially reduce the uptake of dietary triacylglycerol aiding in weight management.

Effect of orlistat on plasma leptin levels and risk factors for the metabolic syndrome

BACKGROUND

The aim of this research was to assess the impact of treatment with Orlistat 120 mg three times daily on serum leptin levels, weight loss, glycemic control, and cardiovascular risk factors involved in the metabolic syndrome.

METHODS

A 3-month open-labeled prospective study was conducted on 40 patients with the clinical features of the metabolic syndrome divided into two groups-with and without type 2 diabetes mellitus. Twenty type 2 diabetic obese patients (group A) were studied, with BMI of 35.4 +/- 0.9 kg/m(2), as were 20 obese patients without diabetes (group B), with BMI of 36.2 +/- 0.7 kg/m(2). Weight, serum leptin levels, insulin resistance, and cardiovascular risk factors were measured at baseline and at the end of each month.

RESULTS

Patients reduced weight at 8.5 +/- 2.3 kg for men and 5.7 +/- 2.6 kg for women in group A against 7.9 +/- 1.9 kg for men and 5.6 +/- 2.0 kg for women in group B. Plasma leptin levels decreased at 4.5 +/- 1.9 ng/mL for men and 1.9 +/- 0.9 ng/mL for women in group A against 3.8 +/- 2.0 ng/mL for men and 2.8 +/- 1.4 ng/mL for women in group B. The level of insulin resistance measured with HOMA-IR decreased from 4.54 +/- 2.35 to 2.69 +/- 0.86 in group A against 3.98 +/- 1.89 to 2.87 +/- 0.93 in group B. In the lipid parameters, the highest decrease was found in triglycerides levels: 6.1 +/- 2.3 mmol/L for men and 3.5 +/- 2.6 mmol/L for women in group A against 2.1 +/- 1.9 mmol/L for men and 1.8 +/- 0.7 mmol/L for women in group B (all p < 0.05).

CONCLUSIONS

Orlistat beneficially enhances weight loss, contributing to a decrease of serum leptin, insulin resistance level, and cardiovascular risk factors in both groups. An additional beneficial pleotropic effect of Orlistat could be proposed through a reduction of plasma leptin and lipid levels.

Postprandial effect of orlistat on the peaking of lipid level after sequential high fat meals

BACKGROUND

Postprandial lipemia has been found to be strongly associated with atherosclerosis due to its atherogenic and thrombogenic lipoprotein changes. This phenomenon occurs even in normal subjects especially after high fat meals. Orlistat, an anti- obesity drug, has been shown to address postprandial lipemia after a single high fat meal.

OBJECTIVES

To compare the effects of orlistat and placebo on the postprandial lipid levels after sequential high-fat meals in healthy individuals with normal fasting lipid levels.

PATIENTS AND METHODS

Thirty-one healthy adult volunteers with normal fasting lipid levels were fed 50% fat meals (3 meals and 2 snacks of pre-weighted butter and bread). The subjects were blindly randomized to receive either placebo or orlistat 120 mg before each main meal. The outcome parameters were total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and very-low-density lipoprotein (VLDL) cholesterol levels measured at fasting (0 h) and every 2 h thereafter, until the sixteenth hour. Additionally, we estimated the lipid levels at the fifth and ninth hour.

RESULTS

The non-orlistat group showed a significant postprandial rise in the levels of TG and VLDL, which began 4 h after breakfast (P < 0.05); this rise in levels was sustained until 9 h after breakfast for TG and up to 10 h after breakfast for VLDL. In contrast, only one significant rise in both TG and VLDL levels (at 4 h after breakfast) was noted in the orlistat group. The maximum mean difference from the baseline TG level for the orlistat group was lower than that for the non-orlistat group (0.22 mmol/L vs. 0.756 mmol/L, respectively). Similarly, the maximum mean difference from the baseline VLDL level from baseline in the orlistat group was only 0.099 mmol/L, which was lower than that in the non-orlistat group (0.588 mmol/L). LDL levels rose to a lesser extent in the orlistat group than in the non-orlistat group (0.268 vs. 0.362 mmol/L). The TC levels did not show a postprandial rise; instead, the levels reduced in both groups, with the orlistat group showing a higher reduction than the non-orlistat group (-0.288 vs. -0.188 mmol/L). The orlistat group did not show any significant differences in the HDL measurements.

CONCLUSIONS

Administration of orlistat abolished the significantly sustained postprandial rise of TG and VLDL levels in healthy individuals who were fed sequential 50% fat meals.

The use of serotonergic drugs to treat obesity--is there any hope?

Surgical interventional strategies for the treatment of obesity are being implemented at an increasing rate. The safety and feasibility of these procedures are questionable for most overweight or obese individuals. The use of long-term pharmacotherapy options, on the other hand, can target a greater portion of the obese population and provide early intervention to help individuals maintain a healthy lifestyle to promote weight loss. Medications that act on the central serotonergic pathways have been a relative mainstay for the treatment of obesity for the last 35 years. The clinical efficacy of these drugs, however, has been encumbered by the potential for drug-associated complications. Two drugs that act, albeit by different mechanisms, on the central serotonergic system to reduce food intake and decrease body weight are sibutramine and lorcaserin. Sibutramine is a serotonin and norepinephrine reuptake inhibitor, whereas lorcaserin is a selective 5HT_2C receptor agonist. The recent worldwide withdrawal of sibutramine and FDA rejection of lorcaserin has changed the landscape not only for serotonin-based therapeutics specifically, but for obesity pharmacotherapy in general. The purpose of this review is to focus on the importance of the serotonergic system in the control of feeding and its potential as a target for obesity pharmacotherapy. Advances in refining and screening more selective receptor agonists and a better understanding of the potential off-target effects of serotonergic drugs are needed to produce beneficial pharmacotherapy.

The pharmacological treatment and management of obesity

Obesity is a pandemic with many complications that increase the societal disease burden and cost of health care, and decrease longevity and quality of life. Currently, 1 in 3 adults in the United States is obese. Physicians must therefore regularly confront obesity and its consequent diseases, and develop strategies for effective treatment and management. This article summarizes current lifestyle modifications, pharmacological treatment, and surgical options for the management of obesity and discusses the benefits, limitations, and risks of each. As insights are gained into the pathophysiology of a gut-brain neurochemical feedback axis governing satiety and feeding behavior, targets for new pharmacotherapies are being developed. In particular, gut hormone analogs are an attractive antiobesity therapy because they appear to lack the adverse effects historically associated with central nervous system-acting agents.

Comparison between orlistat plus l-carnitine and orlistat alone on inflammation parameters in obese diabetic patients

To evaluate the effects of 1-year treatment with orlistat plus L-carnitine compared to orlistat alone on body weight, glycemic and lipid control, and inflammatory parameters in obese type 2 diabetic patients. Two hundred and fifty-eight patients with uncontrolled type 2 diabetes mellitus (T2DM) [glycated hemoglobin (HbA(1c)) > 8.0%] in therapy with different oral hypoglycemic agents or insulin were enrolled in this study and randomized to take orlistat 120 mg three times a day plus L-carnitine 2 g one time a day or orlistat 120 mg three times a day. We evaluated the following parameters at baseline and after 3, 6, 9, and 12 months: body weight, body mass index (BMI), glycated hemoglobin (HbA(1c) ), fasting plasma glucose (FPG), postprandial plasma glucose (PPG), fasting plasma insulin (FPI), homeostasis model assessment insulin resistance index (HOMA-IR), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (Tg), adiponectin (ADN), leptin, tumor necrosis factor-α (TNF-α), vaspin, and high-sensitivity C-reactive protein (Hs-CRP). We observed a better decrease in body weight, glycemic profile, HOMA-IR, LDL-C, and ADN and a faster improvement in FPI, TC, Tg, leptin, TNF-α, Hs-CRP with orlistat plus L-carnitine compared to orlistat alone. We also recorded an improvement in vaspin with orlistat plus l-carnitine not reached with orlistat alone. Orlistat plus L-carnitine gave a better improvement in body weight, glycemic and lipid profile compared to orlistat alone; furthermore, a faster and better improvement in inflammatory parameters was observed with orlistat plus L-carnitine compared to orlistat alone.

Lipase inhibitor orlistat decreases incorporation of eicosapentaenoic and docosahexaenoic acids in rat tissues

Orlistat is a gastric and pancreatic lipases inhibitor that is often prescribed to obese subjects. Orlistat has been shown to decrease the absorption of biologically important lipophilic micronutrients such as liposoluble vitamins. We hypothesized that long-term administration of orlistat may lower the incorporation of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) in blood lipids and tissues. This hypothesis was tested in rats fed a diet supplemented with fish oil as a source of n-3 LC-PUFA. Male Wistar rats (n = 18) were divided into 3 groups and fed experimental high-fat diets containing fish oil (control diet) or fish oil plus orlistat (200 and 400 mg/kg of diet) over the course of 3 weeks. Fat absorption and the level of eicosapentaenoic acid (EPA) and docosahexaenoic acid, among other fatty acids, in red blood cells, plasma, liver, and spleen, were measured at the end of the experimental period. The results show that at 200 mg and 400 mg/kg of diet orlistat lowers fat absorption by 9% (P = .008) and 54% (P = .008). Orlistat given at the higher level induced a reduction of the incorporation of EPA in red blood cell (-45%; P = .006) and in plasma (-34%; P = .026) compared to the control group. Our results confirmed that administration of orlistat reduces incorporation of n-3 LC-PUFA in blood lipids and tissues in a rat model.

Pharmaceutical quality of nine generic orlistat products compared with Xenical(r)

OBJECTIVE

To compare the pharmaceutical quality of Xenical (chemically produced orlistat) with nine generic products, each produced by fermentation processes.

METHODS

Xenical 120 mg capsules (Roche, Basel, Switzerland) were used as reference material. Generic products were from India, Malaysia, Argentina, Philippines, Uruguay, and Taiwan. Colour, melting temperature, crystalline form, particle size, capsule fill mass, active pharmaceutical ingredient content, amount of impurities, and dissolution were compared. Standard physical and chemical laboratory tests were those developed by Roche for Xenical.

RESULTS

All nine generic products failed the Xenical specifications in four or more tests, and two generic products failed in seven tests. A failure common to all generic products was the amount of impurities present, mostly due to different by-products, including side-chain homologues not present in Xenical. Some impurities were unidentified. Two generic products tested failed the dissolution test, one product formed a capsule-shaped agglomerate on storage and resulted in poor (</=15%) dissolution. Six generic products were powder formulations.

CONCLUSIONS

All tested generic orlistat products were pharmaceutically inferior to Xenical. The high levels of impurities in generic orlistat products are a major safety and tolerability concern.

The role of lipid and carbohydrate digestive enzyme inhibitors in the management of obesity: a review of current and emerging therapeutic agents

Obesity is a global epidemic associated with significant morbidity and mortality in adults and ill health in children. A proven successful approach in weight management has been the disruption of nutrient digestion, with orlistat having been used to treat obesity for the last 10 years. Although orlistat-induced weight loss remains modest, it produces meaningful reductions in risk factors for obesity-related conditions such as diabetes and cardiovascular disease. Moreover, this lipase inhibitor is free of the serious side effects that have dogged appetite-suppressing drugs. This success had driven investigation into new generation nutraceuticals, supplements and pharmaceutical agents that inhibit the breakdown of complex carbohydrates and fats within the gut. This review focuses on agents purported to inhibit intestinal enzymes responsible for macronutrient digestion. Except for some synthetic products, the majority of agents reviewed are either botanical extracts or bacterial products. Currently, carbohydrate digestion inhibitors are under development to improve glycemic control and these may also induce some weight loss. However, colonic fermentation induced side effects, such as excess gas production, remain an issue for these compounds. The α-glucosidase inhibitor acarbose, and the α-amylase inhibitor phaseolamine, have been used in humans with some promising results relating to weight loss. Nonetheless, few of these agents have made it into clinical studies and without any clinical proof of concept or proven efficacy it is unlikely any will enter the market soon.

Pharmacotherapy for obesity

Obesity is associated with increased risk of conditions such as hypertension, dyslipidaemia, diabetes mellitus, and obstructive sleep apnoea. Pharmacotherapy for obesity should be considered in combination with lifestyle changes in obese patients, or overweight patients with other conditions that put them at risk of developing heart disease. Sibutramine and orlistat are the only two anti-obesity medications approved for long-term use. Sibutramine is a serotonergic and adrenergic drug that reduces food intake. Orlistat is a gastrointestinal lipase inhibitor that interferes with fat absorption. However, it commonly causes flatulence and diarrhoea. Rimonabant is the first of a series of endocannabinoid receptor antagonists. It was approved by the Committee for Medicinal Products for Human Use of the European Medicines Agency (EMEA) as an adjunct to diet and exercise in treating obesity in 2006. However, despite the extensive clinical trial data, EMEA announced in 2008 that it has recommended suspension of rimonabant because of its psychiatric side effects. Studies evaluating the long-term safety and efficacy of anti-obesity agents are needed.

Fundamentals of cardiometabolic risk factor reduction: achieving and maintaining weight loss with pharmacotherapy or bariatric surgery

Obesity is a major health problem in the United States and many other countries because of its high prevalence and causal relationship with serious medical comorbidities. The therapeutic options currently available to help obese patients lose weight are: (1) therapeutic lifestyle change (behavioral, dietary, and physical activity modification); (2) pharmacotherapy; and (3) bariatric surgery. Lifestyle modification is the first therapeutic choice; however, achieving a successful long-term weight loss with lifestyle intervention alone is difficult. There is increasing interest, therefore, in the use of pharmacotherapy and surgery to treat obesity. Although there are a number of antiobesity medications available, the only medications approved in the United States for long-term treatment of obesity are sibutramine and orlistat. Use of these medications results in 3% to 5% more weight loss compared with placebo after 1 year. Bariatric surgery is an effective weight loss option for obese patients, but it is restricted to patients who are considered morbidly obese (ie, with a body mass index [BMI] > or =40 kg/m(2) or a BMI of 35-39.9 kg/m(2) with > or =1 severe obesity-related medical complication).

The prince and the pauper. A tale of anticancer targeted agents

Cancer rates are set to increase at an alarming rate, from 10 million new cases globally in 2000 to 15 million in 2020. Regarding the pharmacological treatment of cancer, we currently are in the interphase of two treatment eras. The so-called pregenomic therapy which names the traditional cancer drugs, mainly cytotoxic drug types, and post-genomic era-type drugs referring to rationally-based designed. Although there are successful examples of this newer drug discovery approach, most target-specific agents only provide small gains in symptom control and/or survival, whereas others have consistently failed in the clinical testing. There is however, a characteristic shared by these agents: -their high cost-. This is expected as drug discovery and development is generally carried out within the commercial rather than the academic realm. Given the extraordinarily high therapeutic drug discovery-associated costs and risks, it is highly unlikely that any single public-sector research group will see a novel chemical "probe" become a "drug". An alternative drug development strategy is the exploitation of established drugs that have already been approved for treatment of non-cancerous diseases and whose cancer target has already been discovered. This strategy is also denominated drug repositioning, drug repurposing, or indication switch. Although traditionally development of these drugs was unlikely to be pursued by Big Pharma due to their limited commercial value, biopharmaceutical companies attempting to increase productivity at present are pursuing drug repositioning. More and more companies are scanning the existing pharmacopoeia for repositioning candidates, and the number of repositioning success stories is increasing. Here we provide noteworthy examples of known drugs whose potential anticancer activities have been highlighted, to encourage further research on these known drugs as a means to foster their translation into clinical trials utilizing the more limited public-sector resources. If these drug types eventually result in being effective, it follows that they could be much more affordable for patients with cancer; therefore, their contribution in terms of reducing cancer mortality at the global level would be greater.

Effect of weight-reducing agents on glycaemic parameters and progression to Type 2 diabetes: a review

Weight loss is associated with improvements in glycaemic control and cardiovascular disease risk factors. However, in the diabetic population, weight management is more challenging, in part because of the weight-promoting effects of the majority of glucose-lowering therapies. This review summarizes evidence from 23 placebo-controlled randomized trials, of at least 1 year duration, on the effects of drugs promoting weight loss (orlistat, sibutramine and rimonabant) on glycaemic variables, diabetes incidence and diabetes control. Fifteen studies of non-diabetic subjects were found, eight of which included a longer treatment period. Eight studies in diabetic patients were reviewed. In non-diabetic subjects, weight loss agents led to a significant improvement in fasting glucose, fasting insulin and insulin resistance. In the diabetic population, glycated haemoglobin decreased by 0.28-1.1% with orlistat and 0.6% with sibutramine and rimonabant. Orlistat reduces progression to diabetes in patients with glucose intolerance treated for 4 years (risk reduction of 45%). In summary, despite leading to only modest weight loss after 12 months, agents promoting weight loss have beneficial effects on glycaemic parameters, glycaemic control and progression to diabetes. These additional benefits of weight loss agents need to be highlighted in order to increase their judicious use in clinical practice, although this may be limited by their well-known adverse side effects. The longer-term safety of these agents beyond a few years is yet to be established.

Orlistat-associated adverse effects and drug interactions: a critical review

Orlistat, an anti-obesity drug, is a potent and specific inhibitor of intestinal lipases. In light of the recent US FDA approval of the over-the-counter sale of orlistat (60 mg three times daily), clinicians need to be aware that its use may be associated with less well known, but sometimes clinically relevant, adverse effects. More specifically, the use of orlistat has been associated with several mild-to-moderate gastrointestinal adverse effects, such as oily stools, diarrhoea, abdominal pain and faecal spotting. A few cases of serious hepatic adverse effects (cholelithiasis, cholostatic hepatitis and subacute liver failure) have been reported. However, the effects of orlistat on non-alcoholic fatty liver disease are beneficial. Orlistat-induced weight loss seems to have beneficial effects on blood pressure. No effect has been observed on calcium, phosphorus, magnesium, iron, copper or zinc balance or on bone biomarkers. Interestingly, the use of orlistat has been associated with rare cases of acute kidney injury, possibly due to the increased fat malabsorption resulting from the inhibition of pancreatic and gastric lipase by orlistat, leading to the formation of soaps with calcium and resulting in increased free oxalate absorption and enteric hyperoxaluria. Orlistat has a beneficial effect on carbohydrate metabolism. No significant effect on cancer risk has been reported with orlistat.Orlistat interferes with the absorption of many drugs (such as warfarin, amiodarone, ciclosporin and thyroxine as well as fat-soluble vitamins), affecting their bioavailability and effectiveness. This review considers orlistat-related adverse effects and drug interactions. The clinical relevance and pathogenesis of these effects is also discussed.

Compliance, behavior change, and weight loss with orlistat in an over-the-counter setting

OBJECTIVE

The study was conducted to provide information on how consumers would use orlistat 60 mg, especially in terms of product dosing, in a setting without physician supervision.

METHODS AND PROCEDURES

A 3-month, open-label, naturalistic study was conducted in an over-the-counter (OTC) setting in 18 pharmacies. Consumers >/=18 years were allowed to purchase orlistat packages containing a bottle of orlistat 60 mg plus educational materials, which provided lifestyle information and tools to encourage successful weight loss. Data were collected at pharmacy visits and during telephone interviews at 14, 30, 60, and 90 days after enrollment.

RESULTS

A total of 237 subjects purchased and used the product, and completed at least one interview. Most subjects followed the dosing directions and took two to three capsules per day with meals throughout the study. The majority of subjects took a daily multivitamin, as directed. Approximately, 80% of subjects used the educational materials and found them useful or very useful. Over the study duration, most subjects reported following a diet and 51% of subjects reported more frequent or longer exercise than at enrollment. Approximately, 80% of subjects indicated they were satisfied or very satisfied with the weight loss achieved; measured and self-reported relative median weight loss was approximately 5% after > or =60 days of using orlistat. Most common adverse events were gastrointestinal (GI), and majority of subjects did not interrupt or discontinue orlistat due to these GI events.

DISCUSSION

These results demonstrate that orlistat 60 mg can be used appropriately and safely and with high consumer satisfaction without physician supervision or dietary counseling. Collectively, results indicate that orlistat 60 mg is an appropriate weight loss therapy in the OTC environment.

Recommendations for treatment of child and adolescent overweight and obesity

In this article, we review evidence about the treatment of obesity that may have applications in primary care, community, and tertiary care settings. We examine current information about eating behaviors, physical activity behaviors, and sedentary behaviors that may affect weight in children and adolescents. We also review studies of multidisciplinary behavior-based obesity treatment programs and information about more aggressive forms of treatment. The writing group has drawn from the available evidence to propose a comprehensive 4-step or staged-care approach for weight management that includes the following stages: (1) Prevention Plus; (2) structured weight management; (3) comprehensive multidisciplinary intervention; and (4) tertiary care intervention. We suggest that providers encourage healthy behaviors while using techniques to motivate patients and families, and interventions should be tailored to the individual child and family. Although more intense treatment stages will generally occur outside the typical office setting, offices can implement less intense intervention strategies. We not ony address specific patient behavior goals but also encourage practices to modify office systems to streamline office-based care and to prepare to coordinate with professionals and programs outside the office for more intensive interventions.

Management of Obesity in Patients with Peripheral Arterial Disease

Obesity is a major risk factor for cardiovascular disorders, including peripheral arterial disease. This review outlines the evidence for a 6-step process for the management of obesity, starting with identifying the degree and type of obesity, followed by target setting, life style and behavioural changes, imposed hypocaloric diet and physical activity, pharmacological treatment and consideration of eating disorders and/or bariatric surgery.

Effect of orlistat on fecal fat, fecal biliary acids, and colonic cell proliferation in obese subjects

BACKGROUND & AIMS

Orlistat is a weight management agent that selectively inhibits gastrointestinal lipase activity. Because of orlistat's mode of action, increased fecal fat is presented to the colonic mucosa, and fecal bile acid and free fatty acid composition may be altered during treatment. Our aim was to assess the effect of treatment of obese subjects with orlistat 120 mg 3 times a day for 6 weeks on fecal lipid and bile acid parameters and colonic mucosal cell proliferation.

METHODS

Twenty-four obese (body mass index, 30-40 kg/m2) but otherwise healthy male and female subjects were enrolled in a single-center, randomized, double-blind, placebo-controlled, parallel-group study. Participants were hospitalized during days 1-3 and 33-42 of treatment and were treated as outpatients for the remaining days.

RESULTS

Treatment with orlistat for 6 weeks resulted in significantly greater increases in fecal weight, total fecal fat, and fecal free fatty acids than placebo. Total fecal bile acid amounts decreased slightly with orlistat, and increased significantly with placebo treatment (P < .05 between-group difference). Orlistat did not alter colonic cell proliferation as assessed by the 3 proliferative indices (5-bromo-2-deoxyuridine, whole crypt mitotic count, and proliferating cell nuclear antigen).

CONCLUSIONS

Biochemical changes in fecal composition related to the pharmacodynamic mode of action of orlistat are not accompanied by altered colonic cell proliferation, a putative biomarker of colon cancer risk.

Orlistat for the management of overweight individuals and obesity: a review of potential for the 60-mg, over-the-counter dosage

Orlistat, in the 60-mg over-the-counter dose, was recently approved by the FDA. This lipase inhibitor blocks absorption of ~25% of ingested fat and has ~85% of the efficacy of the 120-mg dose for weight loss. Over 16 weeks weight loss with diet and orlistat 60 mg averages ~5% of initial body weight. The 60-mg dose is better tolerated than the 120-mg dose and the gastrointestinal side effects are minimal when individuals consume < 30% of their energy from fat. In addition to facilitating modest weight loss, orlistat use decreases serum LDL-cholesterol values by ~10%. When taken three times daily before meals, orlistat 60 mg modifies lifestyle behavior, encourages lower fat-consumption and sets the stage for other healthy lifestyle changes.

How effective are lifestyle changes in the prevention of type 2 diabetes mellitus?

Obesity and impaired glucose tolerance are associated with a greater risk for a number of conditions, including insulin resistance, diabetes mellitus, hypertension, dyslipidemia, coagulation abnormalities, inflammatory markers, and coronary heart disease. Lifestyle changes can delay or prevent the development of type 2 diabetes in patients with obesity and impaired glucose tolerance. The risks improve with weight loss and increased physical activity. A decrease of 7% to 10% or more from baseline weight can have a significant effect. This has now been documented in a number of randomized, controlled studies.

HPLC analysis of orlistat and its application to drug quality control studies

In this study, a high performance liquid chromatography method with UV detection was developed for determination of orlistat. The chromatographic system consisted of a Nova-Pack C18 column, an isocratic mobile phase of phosphoric acid 0.1%-acetonitrile (10 : 90, v/v) and UV detection at 205 nm. Orlistat was eluted at about 6 min with no interfering peak from excipients used for preparation of dosage form. The method was linear over the range of 10-160 microg/ml orlistat (r2 > 0.9999). The within-day and between-day precision values were also in the range of 0.10-0.59%. The appropriate dissolution conditions were also determined and applied to evaluate the dissolution profile of orlistat capsules. Optimal conditions were 1000 ml of 3% SLS in water as dissolution medium and paddle at 100 rotation per minute. The proposed method was applied successfully to the determination of orlistat content in capsules and in vitro dissolution studies.

The Obesity Epidemic: Current and Future Pharmacological Treatments

The unabated rise in the prevalence of obesity is a challenge for global health care systems. Efforts to reverse this trend by dietary or behavioral counseling have not been successful, which has stimulated efforts to find a role for pharmacotherapy. Currently only a small number of antiobesity drugs are approved for long-term use and only a few compounds are in clinical development. Despite recent progress in the understanding of the regulation of energy balance, drug discovery has been less productive than expected. In the present review, the clinically available antiobesity agents are discussed. Examples of drug candidates that are currently in development are given and the possible future range of antiobesity agents is illustrated by the targets being addressed in drug discovery. Finally, the efficacy of antiobesity agents and their value in the treatment of obesity are assessed in comparison with other therapeutic approaches, such as surgery and changes in lifestyle.

Effect of fat digestion on superior mesenteric artery blood flow in humans

BACKGROUND AND AIM

Intraluminal nutrients stimulate superior mesenteric artery (SMA) blood flow. Of the macronutrients, especially fat affects the magnitude of the SMA blood flow response to a meal. Little is known however on the influence of fat hydrolysis on SMA flow.

METHODS

We compared in eight healthy volunteers the SMA flow response (Doppler ultrasonography) to continuous intraduodenal fat perfusion (LCT, 240 kCal h(-1)) during conditions with normal hydrolysis (placebo, control), increased hydrolysis (pancreatic enzyme supplementation; 50 kU lipase) and impaired hydrolysis (orlistat 240 mg).

RESULTS

Intraduodenal LCT significantly (P<0.01) increased SMA flow in all experiments over basal. The SMA flow response to fat during pancreatic enzyme supplementation (1.49 +/- 0.1 l min(-1)) was significantly (P<0.05) higher compared with placebo (1.11 +/- 0.16 l min(-1)). Lipase inhibition with orlistat did not significantly affect fat stimulated SMA flow compared with placebo: 0.89 +/- 0.08 l min(-1) versus 1.11 +/- 0.16 l min(-1).

CONCLUSIONS

Administration of pancreatic enzymes significantly increases fat stimulated SMA flow. Fat digest products in the intestinal lumen contribute to the regulation of SMA blood flow.

Effect of orlistat in overweight poorly controlled Chinese female type 2 diabetic patients: a randomised, double-blind, placebo-controlled study

The aim of the study was to assess the adjunctive effects of orlistat on weight loss and the influence of weight reduction on glycaemic control in overweight Chinese female type 2 diabetic patients. A randomised, placebo-controlled, double-blind, 12-week study was conducted. Chinese female type 2 diabetic patients, overweight (body mass index > 25 kg/m(2)), poorly controlled glucose levels [glycosylated haemoglobin (HbA1c) > 8%], were randomly assigned to two groups. In addition to their oral hypoglycaemic agents (maximal doses of sulphonylureas and metformin), one group (n = 30) received a placebo and the other (n = 30) received orlistat 120 mg t.i.d. for 12 weeks. Comparing the changes that occurred after 12 weeks in the orlistat and placebo groups, the former showed significantly greater reduction in bodyweight (2.5 vs. 0.4 kg; p < 0.05), fasting plasma insulin level (p < 0.01), 2-h postprandial blood glucose after glucose challenge (p < 0.01), insulin resistance (p < 0.01), HbA1c (p < 0.05), total cholesterol and triglyceride levels (p < 0.05, respectively). No significant differences were found between treatment groups in blood pressure and heart rate. The addition of orlistat to oral hypoglycaemic agents resulted in a significant weight reduction and improvement of metabolic control in overweight Chinese female type 2 diabetic patients.

Polyphenol-enriched oolong tea increases fecal lipid excretion

OBJECTIVE

To assess possibility of polyphenol-enriched oolong tea to reduce dietary lipid absorption in humans.

DESIGN

Twelve healthy adult subjects, three males and nine females, aged (mean+/-s.d.) 22.0+/-1.8 years, respectively, were randomly divided into two groups. The participants were followed a double-blind placebo-controlled crossover design, including 7-day washout periods and 10-day treatment periods. During the treatment periods, subjects were given about 38 g of lipids from potato chips (19 g each within 30 min after lunch and dinner) and total 750 ml beverages (placebo- or polyphenol-enriched oolong tea) at three meals. Blood samples were collected for biochemical examination at days 8, 18, 25 and 35 of the study period. On the last 3 days of each treatment period, feces were collected to measure the excretion of lipids.

RESULTS

Lipid excretion into feces was significantly higher in the polyphenol-enriched oolong tea period (19.3+/-12.9 g/3 day) than in the placebo period (9.4+/-7.3 g/3 day) (P < 0.01). Cholesterol excretion tended to increase in polyphenol-enriched oolong tea period (1.8+/-1.2 g/3 day) compared with that of placebo (1.2+/-0.6 g/3 day) (P = 0.056).

CONCLUSIONS

The results of this study indicated that polyphenol-enriched oolong tea could increase lipid excretion into feces when subjects took high-lipid diet.

Influences of fat restriction and lipase inhibition on gastric emptying in obesity

OBJECTIVE

Accelerated gastric emptying of solids may play a role in the pathogenesis of obesity. Orlistat, a potent lipase inhibitor, induces fat malabsorption and body weight loss but might accelerate gastric emptying as a result of suppressed CCK release. The aim was to investigate the role of fat restriction and lipase inhibition in CCK release and gastric emptying.

SUBJECTS

A total of 28 patients (three male (M)/25 female (F); mean (s.d.) BMI 37.4(3.9) kg/m2) entering a randomized, double-blind, placebo-controlled study.

MEASUREMENTS

CCK release and gastric emptying by scintigraphy at the start (T0), after 1 month of an energy- and fat-restricted diet and placebo (T1), and after 1 month (T2) and 1 year (T3) of randomization to placebo or 120 mg orlistat three times a day.

RESULTS

One month of dieting and a weight loss of 2.3 kg (2.1% of initial weight) did not affect gastric emptying of liquids and solids. Basal and meal-stimulated CCK levels remained unaltered. Placebo-treated subjects who continued the diet for 1 month demonstrated a borderline significant suppressed CCK secretion and a weight loss of 1.2 kg (1.0%) without an effect on gastric emptying. After 1 year, the CCK secretion recovered to or beyond values at the start. A significantly slower emptying of solids (17.6 (T3) versus 25.9 (T1)%/h) and a weight loss of 10.4 kg (9.9%) was observed. Subjects on 120 mg orlistat lost 2.5 kg (2.5%) after 1 month, and 9.8 kg (9.9%) after 1 year. Basal and postprandial CCK release decreased significantly after the first month of orlistat treatment but normalized after 1 year. Diet and lipase inhibition did not have any influence on gastric emptying.

CONCLUSION

Energy and fat restriction of 1 month did not alter gastric emptying in the whole group. Continuation of the diet for 1 year resulted in a delayed gastric emptying of solids. Lipase inhibition did not result in a sustained depressed CCK release and the anticipated acceleration of gastric emptying did not occur.

Orlistat in the treatment of overweight or obese Chinese patients with newly diagnosed Type 2 diabetes

AIMS

Orlistat promotes weight loss in overweight and obese patients with Type 2 diabetes receiving hypoglycaemic treatment, but has not been investigated in patients with newly diagnosed and previously untreated Type 2 diabetes. We evaluated the efficacy of 24 weeks' treatment with orlistat, combined with a mildly reduced-calorie diet, on weight loss and glycaemic control in overweight and obese patients with newly diagnosed and previously untreated Type 2 diabetes.

METHODS

A total of 249 Chinese patients (body mass index 25-40 kg/m2) with recently diagnosed Type 2 diabetes were randomized to placebo (n=124) or orlistat 120 mg (n=125) three times daily; all patients followed a mildly reduced-calorie diet. Patients had HbA1c 6.5-8.5% (mean 7.3%) and had never received any glucose-lowering medication.

RESULTS

Orlistat-treated patients achieved significantly greater weight loss at the study end than placebo-treated patients (-5.4 vs. -2.4 kg; P<0.0001). More orlistat than placebo patients lost>or=5% (60.5 vs. 26.8%; P<0.0001) and >or=10% of their body weight (20.2 vs. 4.9%; P=0.0002). A significantly greater decrease in HbA(1c) from baseline was obtained with orlistat than placebo (-1.0 vs. -0.6%; P=0.0008). Orlistat-treated patients achieved a significantly greater decrease in fasting plasma glucose (-1.3 vs. -0.5 mmol/l; P=0.0003) and in the 2-h oral glucose tolerance test (-4.1 vs. -1.4 mmol/l; P<0.0001) than placebo recipients. Also, more orlistat- than placebo-treated patients improved from diabetic status to normal or impaired glucose tolerance (44.3 vs. 32.5%; P=0.0763) after 24 weeks. Orlistat also produced improvements in lipid profiles and waist circumference.

CONCLUSIONS

In combination with a mildly reduced-calorie diet, orlistat significantly reduces body weight, and improves glycaemic control and several cardiovascular risk factors in overweight and obese Chinese patients with newly diagnosed Type 2 diabetes.

Effect of Orlistat in obese patients with heart failure: a pilot study

Heart failure is the leading cause of hospitalization. Obesity is increasingly common and is a major public health problem. The aim of this study is to assess whether obese patients with heart failure can benefit from losing weight via an orlistat-assisted diet. This randomized clinical trial included obese patients with ejection fractions < or =40%. Orlistat and diet counseling were compared with diet counseling alone. Twenty-one consecutive obese patients with heart failure were recruited. Significant improvement in 6-minute walk test (45.8 m; 95% confidence interval, 5.2-86.4 m; p=0.031), functional class (-0.6+/-0.5, p=0.014), weight loss (-8.55 kg; 95% confidence interval, -13.0 to -4.1 kg; p<0.001) and also significant decreases in total cholesterol (p=0.017), low-density lipoprotein cholesterol (p=0.03), and triglycerides (p=0.036) were observed in the orlistat group. Orlistat can promote significant weight loss and symptoms of relief in obese patients with heart failure, as measured by 6-minute walk test and functional capacity. The lipid profile improved. Orlistat was safe and well tolerated.

The effects of loperamide on continence problems and anorectal function in obese subjects taking orlistat

Continence problems during treatment with orlistat (a lipase inhibitor) are caused when susceptible patients are exposed to increased volumes of loose, fatty stool.

AIM

To investigate the dose-response effects of loperamide on continence and anorectal function in subjects susceptible to continence problems on orlistat.

METHOD

Ten obese subjects enterred a randomized controlled, double-blind study of loperamide at placebo, 2, 4, and 6 mg/day in a factorial design. Continence problems during orlistat treatment were self-assessed by patient diary. Anorectal function and continence were assessed by barostat, manometry, and retention testing.

RESULTS

Loperamide increased stool consistency with dose (p = 0.07) and this effect reduced continence problems during orlistat treatment (p < 0.05). A bell-shaped dose-response relationship was present with anal sphincter function (p < 0.01) and anorectal sensitivity (p < 0.01).

CONCLUSION

Loperamide has beneficial effects on stool consistency and continence in obese subjects taking orlistat. The effect on stool consistency appeared more important than effects on anorectal function.