Sibutramine Effects on Central Mechanisms Regulating Energy Homeostasis

During the last 50 years the global pandemic of obesity and associated life-threatening co-morbidities strongly promoted the development of anti-obesity pharmacotherapy. Sibutramine is an anti-obesity drug that in conjunction with lifestyle modifications reduces food intake and body weight. This may result from several effects: inhibition of presynaptic reuptake of monoaminergic neurotransmitters in the central nervous system, thereby suppressing appetite, induction of an increase in anorexigenic and a decrease in orexigenic neuropeptide secretion, induction of an increase in energy expenditure, and induction of peripheral sympathomimetic effects. The effects of sibutramine on anabolic and catabolic signals that regulate energy homeostasis in the hypothalamus are not completely understood. So, the aim of this review is to summarize the central mechanisms of action of sibutramine, responsible for its weight and food intake reducing potential. Despite being a useful drug in obesity treatment, awareness about the loss of long-term effectiveness and detrimental side effects of sibutramine has recently emerged. As a consequence, new drugs that produce safer and more persistent weight loss are currently undergoing clinical trials.     

Sibutramine: current status as an anti-obesity drug and its future perspectives

Background: Obesity has become a global epidemic with recent estimates of > 400 million obese adults. Despite this, there are few safe and effective pharmacological interventions for obesity. Sibutramine is a weight loss agent, for use as an adjuvant to a comprehensive program of calorie restriction, exercise and behavioral therapy. Objective: The goal of this article is to review the available literature of pharmacological interventions for obesity and specifically to examine data with sibutramine for the short term on safety and efficacy for weight loss. Methods: The literature on sibutramine was reviewed after a PubMed and Medline search in March 2008. All randomized clinical trails were reviewed. Results/conclusions: Sibutramine appears to be safe and effective in producing clinically significant weight loss for up to 1 year. Longer prospective clinical studies with sibutramine are needed to evaluate its safety (effect on blood pressure) and ability to maintain weight loss, improve metabolic profiles and reduce the risk of cardiovascular diseases.     

Pharmacotherapy for obesity

Pharmacotherapy for the management of obesity is primarily aimed at weight loss, weight loss maintenance and risk reduction, and has included thyroid hormone, amphetamines, phentermine, amfepramone (diethylpropion), phenylpropanolamine, mazindol, fenfluramines and, more recently, sibutramine and orlistat. These agents decrease appetite, reduce absorption of fat or increase energy expenditure. Primary endpoints used to evaluate anti-obesity drugs most frequently include mean weight loss, percentage weight loss and proportion of patients losing >or=5% and >or=10% of initial bodyweight. Secondary endpoints may include reduction in body fat, risk factors for cardiovascular disease and the incidences of diseases such as diabetes mellitus. Most pharmacotherapies have demonstrated significantly greater weight loss in patients on active treatment than those receiving placebo in short-term (or=10% loss of initial bodyweight in 46% of patients. For patients taking orlistat, weight loss was 2.2 kg greater than those on placebo at 4 years (p<0.001), with significantly more patients achieving >or=10% loss of initial bodyweight (26.2% and 15.6%, respectively; p<0.001). Other drugs that have been evaluated for weight loss include ephedrine, the antidepressants fluoxetine and bupropion, and the antiepileptics topiramate and zonisamide. Two clinical trials with fluoxetine both reported no significant difference in weight loss compared with placebo at 52 weeks. Clinical trials evaluating ephedrine, bupropion, topiramate and zonisamide have demonstrated significantly greater weight loss than placebo but have been limited to 16-26 weeks' treatment. A major obstacle to the evaluation of the clinical trials is the potential bias resulting from low study completion rates. Completion rates varied from 52.8% of phentermine recipients in a 9-month study, to 40% of fenfluramine recipients in a 24-week comparative study with phentermine and 18% of amfepramone recipients in a 24-week study. One-year completion rates range from 51% to 73% for sibutramine and from 66% to 85% for orlistat. Other potential sources of bias include run-in periods and subsequent patient selection based on compliance or initial weight loss. Several potential new therapies targeting weight loss and obesity through the CNS pathways or peripheral adiposity signals are in early phase clinical trials. Over the next decade the drug treatment of obesity is likely to change significantly because of the availability of new pharmacotherapies to regulate eating behaviours, nutrient partitioning and/or energy expenditure.     

盐酸西布曲明对高脂肥胖大鼠下丘脑增食欲素系统的影响

目的观察盐酸西布曲明对高脂饮食肥胖大鼠下丘脑增食欲素系统基因表达的变化。方法建立高脂饮食肥胖大鼠模型,分组连续灌胃给药4wk,观察盐酸西布曲明给药对高脂饮食肥胖大鼠体重、血脂、血糖及下丘脑前增食欲素原及增食欲素受体mRNA表达的影响。结果盐酸西布曲明8mg·kg-1能明显降低高脂肥胖大鼠体重、血糖和血脂;升高肥胖大鼠下丘脑前增食欲素原mRNA表达水平;各组间增食欲素受体1和2mRNA表达无变化。结论盐酸西布曲明具有减重、降脂和增加高脂饮食肥胖大鼠下丘脑前增食欲素原基因表达的作用。     

A review of the metabolic effects of sibutramine

BACKGROUND: Obesity is associated with an increased incidence of diabetes, hypertension, dyslipidaemia and coronary artery disease. Current management strategies of obesity include lifestyle management strategies of obesity include lifestyle interventions and pharmaco therapy. Sibutramine is a drug with established efficacy in weight reduction and maintenance of weight loss. It reduces food intake and attenuates the fall in reduces food intake and attenuates the fall in metabolic rate associated with weight loss. OBJECTIVE: To review the metabolic effects associated with sibutramine use. METHODS: Relevant articles were identified through a Medline search (up to December 2004). RESULTS: Weight loss with sibutramine treatment is associated with improved insulin sensitivity and a fall in glycosylated haemoglobin levels in type 2 diabetic patients. In most trials sibutramine exerted favourable effects on lipids, especially exerted favourable effects on lipids, especially on high density lipoprotein (HDL) cholesterol and triglycerides, as well as on the total:HDL cholesterol ratio. Sibutramine also lowers serum uric acid concentrations. Furthermore, this drug seems to favourably influence adipocytokines; it reduces serum leptin and resistin levels and increases adiponectin levels. Sibutramine also exerts a beneficial effect on hyper androgenaemia in obese women with polycystic ovary syndrome. Preliminary findings also suggest that weight loss following treatment with sibutramine is useful in patients with non-alcoholic fatty liver disease (NAFLD). CONCLUSION: Weight loss following sibutramine administration is associated with several favourable metabolic effects.     

A benefit-risk assessment of sibutramine in the management of obesity.

Obesity is a multifactorial, chronic disorder that has reached epidemic proportions in most industrialised countries and is threatening to become a global epidemic. Clinical management of obese patients is complex and serious doubts have arisen with regard to safety and efficacy of drug therapy. Following the withdrawal of fenfluramine and dexfenfluramine in 1997, interest has focused on novel anti-obesity drugs. Pharmacological approaches to the management of obesity can, in broad terms, use different distinct strategies: firstly, to reduce energy intake; secondly, to increase energy expenditure; and thirdly, to alter the partitioning of nutrients between fat and lean tissue. Sibutramine is a serotonin-noradrenaline (norepinephrine) reuptake inhibitor indicated for the management of obesity in conjunction with a reduced calorie diet. The pharmacological mechanisms by which sibutramine exerts its weight loss effect are likely due to a combination of reduced appetite, feelings of satiety and possibly the induction of thermogenesis. The efficacy of sibutramine for inducing initial weight loss and the subsequent maintenance of weight loss is well proven in short- and long-term clinical trials of up to 2 years' duration. Most individual placebo-controlled trials and pooled estimates found that the drug produced statistically significant greater weight loss than placebo at all observed endpoints (weighted mean difference for weight change at 8 weeks: -3.4 kg; mean difference range for weight change at 6 months: -4.0 to -9.1 kg; and at 1 year: -4.1 to -4.8 kg). The most frequent dosage regimen in these trials was 10-20 mg daily. Findings suggested a dose-effect relationship in terms of weight loss. Sibutramine was also associated with better weight maintenance relative to placebo (statistically significant difference). Results from mainly small trials showed that sibutramine produced more favourable outcomes in terms of loss of fat mass, reduction in body mass index and loss of > or = 5-10% of initial bodyweight. The most commonly reported adverse effects of sibutramine are headache, constipation and nausea. Certain adverse events associated with the nervous system, including dizziness, dry mouth and insomnia, are reported by > 5% of patients receiving sibutramine. Increases in blood pressure and heart rate were possible adverse effects that require regular monitoring especially in obese hypertensive patients. Neither left-sided cardiac valve disease nor primary pulmonary hypertension was associated with the use of sibutramine. The assessment of the benefit-risk profile of sibutramine remained positive, although the product must be kept under regular review.     

Clinical use of sibutramine

Since obesity is a chronic disorder, a long-term approach is essential, and modern obesity pharmacotherapy means medicating as an adjunct to diet and physical activity not only to achieve weight loss, but also to maintain it. Sibutramine is a US Food and Drug Administration- and European Committee for Proprietary Medicinal Products-approved medication with demonstrated efficacy in long-term obesity management. It is a norepinephrine-serotonin reuptake inhibitor and produces weight loss by a dual mechanism: reduction of food intake and increase in energy expenditure. Sibutramine is given once daily in doses ranging from 5-15 mg. The amount of weight lost with sibutramine is related to both the dose of the drug and the intensity of the behavioral therapy component. Sibutramine produces a weight loss from baseline of more than 5% in over 75% of patients who are prescribed 15 mg daily, and it produces weight loss that averages 5-8% from baseline, independently of the behavioral approach. Weight loss with sibutramine is associated with improvement in waist circumference, lipids, glycemic control, uric acid and health-related quality of life. Sibutramine use is associated with small increases in mean resting blood pressure, but the individual response is variable and not all patients will have blood pressure increases. The drug is also associated with small increases in mean heart rate and should therefore not be used in patients with a history of cardiac arrhythmia. Because it is a serotonin and norepinephrine reuptake inhibitor, sibutramine should not be used with monoamine oxidase inhibitors or noradrenergic agents, and caution is advised in prescribing sibutramine to patients on selective serotonin reuptake inhibitor antidepressants. Given the growing appreciation for the health benefits that can be achieved with even a relatively small weight loss, physicians must become adept in office approaches to achieve modest weight loss. Sibutramine is a useful adjunct to diet and physical activity approaches and can help selected patients achieve and maintain weight loss with concomitant health benefits.     

Sibutramine for obesity in adolescents

In adolescents, there is an epidemic of being overweight or obese. Sibutramine has been shown to cause sustained loss of weight in adults. In a study based in Mexico City, adolescents with a BMI of 35/36 kg/m², who were put on a hypocaloric diet and undertook physical activity, lost 4.3 kg in 6 months, and this loss was increased to 7.3 kg by sibutramine. Similarly, in a study based in the US, there was a loss of 1.9 kg in the placebo group of obese adolescents with a hypocaloric diet and increased physical activity at the end of 12 months, and this was increased to 6.5 kg in the sibutramine group. Sibutramine has a slight tendency to increase blood pressure and heart rate, and seems to be more effective than orlistat in causing weight loss in adolescents. However, orlistat does not have negative effects on blood pressure. Long-term follow-up studies of sibutramine in adolescents are needed to determine whether the weight loss is maintained, and whether the weight loss translates into better clinical outcomes.     

Pharmacologic options for the treatment of obesity.

Past and current drug therapies for weight loss are discussed. More than 50% of Americans can be categorized as overweight or obese. Obesity is associated with increased mortality and with comorbidities such as hypertension, hyperglycemia, dyslipidemia, coronary artery disease, and certain cancers. According to guidelines for identification, evaluation, and treatment of obesity, patients with a body mass index (BMI) of > or = 30 kg/m2 should attempt to lose weight. Patients with a BMI of > or = 25 kg/m2 plus two or more risk factors or patients with an excessive waist circumference plus two or more risk factors should also attempt to lose weight. The initial goal is a 10% weight reduction in six months achieved through lifestyle changes. If lifestyle changes alone are not effective, then drug therapy may be indicated. Pharmacotherapeutic options for obesity have decreased over the past few years. Fenfluramine, dexfenfluramine, and phenylpropanolamine have been withdrawn because of severe adverse effects, leaving only sympathomimetics, sibutramine, and orlistat as anorectics with FDA-approved labeling. Phentermine has been shown to cause a 5-15% weight loss if given daily or intermittently. Compared with sibutramine and orlistat, phentermine is cheaper, and specific formulations allow once-daily administration. However, phentermine is indicated only for short-term treatment, and tolerance often develops. Common adverse effects associated with phentermine are dry mouth, insomnia, increased blood pressure, and constipation. Sibutramine increases norepinephrine and serotonin levels in the CNS and should not be taken with many antidepressants because of the risk of increased norepinephrine and serotonin levels. Its use is also contraindicated in patients with cardiovascular disease. Orlistat is not systemically absorbed; therefore, it does not cause the systemic adverse effects or drug interactions of phentermine and sibutramine. Orlistat has a cholesterol-lowering effect not seen with other diet medications. However, the three-times-daily administration and frequent gastrointestinal effects limit its use. Sibutramine, phentermine, and orlistat have both positive and negative properties. Choosing among the medications will depend on concurrent disease states and medications, ease of administration, and cost.     

Comparison of the acute pharmacodynamic responses after single doses of ephedrine or sibutramine in healthy, overweight volunteers

OBJECTIVE: With an increase in the incidence of obesity, tremendous effort has been devoted to the development of weight loss agents and the prospective surrogate markers of both a product's efficacy and safety. The objective of the present study was to compare the pharmacodynamic responses of ephedrine and sibutramine using surrogate markers of weight loss potential and potential adverse events. DESIGN AND SUBJECTS: The study was designed as a 5-way, randomized, double-blinded, placebo-controlled trial with 3 single doses of ephedrine sulfate (0.25, 0.5 and 1 mg x kg(-1)) followed by an open-labeled sibutramine (10 mg) treatment. Healthy, mildly overweight (BMI = 25) subjects were administered the respective treatment and pharmacokinetic and pharmacodynamic measurements (body surface temperature, resting metabolic rate, blood pressure, heart rate, glucose, glycerol, nonesterified fatty acids, triglycerides) were obtained for 8 hours post dose and for an additional 4 measurements during the sibutramine treatment period. RESULTS: Sibutramine treatment significantly increased resting metabolic rate compared to the placebo condition. Ephedrine significantly increased heart rate, systolic blood pressure and glucose but did not significantly affect other measurements. CONCLUSION: Both sibutramine and ephedrine have been shown to have weight loss potential, however, they elicit different metabolic and biochemical responses after a single dose. The nontherapeutic responses from these types of compounds may serve as a screening tool for the development of agents in the treatment of obesity.     

The discovery and status of sibutramine as an anti-obesity drug

Sibutramine is a serotonin–norepinephrine reuptake inhibitor indicated for the management of obesity in conjunction with a reduced calorie diet. Though sibutramine was originally evaluated for possible use as an antidepressant, its research development was eventually redirected to evaluate it as an anorexiant. The pharmacological mechanisms by which sibutramine exerts its weight loss effect are likely due to a combination of reduced appetite, feelings of satiety, and possibly the induction of thermogenesis. Its efficacy for inducing an initial weight-loss and the subsequent maintenance of the weight-loss is well proven in short- and long-term clinical trials of up to 2 years duration. In general, sibutramine has been well tolerated. Increases in blood pressure and heart rate are possible adverse effects that require regular monitoring. Sibutramine is one of the few established and well-proven agents for obesity available for use today and should be considered effective in the management of patients requiring pharmacotherapy as part of the multi-modal approach to weight-loss.     

Obesity and cardiovascular physiology: impact of some pharmacological agents

The increase in obesity prevalence is problematic as this condition is associated with health complications such as diabetes and cardiovascular diseases, more particularly when the excess body fat is stored in the deep abdominal region. The mainstay of therapy consists of behavior modification related to obesity such as overeating and physical inactivity. When these lifestyle modifying attempts fail, the use of anti-obesity drugs is warranted. Drug treatment is often indicated but is somewhat limited by the minimal number of well tolerated drugs that have proven to have long-term efficacy in maintaining body weight loss. The currently available drugs, sibutramine and orlistat, appear modestly effective in promoting weight loss. Ongoing studies continue to evaluate other drug treatments that may result in body weight reduction through a number of different mechanisms. Thus, the aim of this review is to present an overview of the current drugs available (particularly sibutramine and orlistat) as well as potential future candidates, and the impact of these agents on obesity and cardiovascular physiology. Furthermore, the therapeutic paradox of sibutramine in preventing obesity will be discussed as well as the beneficial impact of physical exercise on cardiac economy.     

A review of the metabolic effects of sibutramine

ABSTRACT

Background: Obesity is associated with an increased incidence of diabetes, hypertension, dyslipidaemia and coronary artery disease. Current management strategies of obesity include lifestyle interventions and pharmacotherapy. Sibutramine is a drug with established efficacy in weight reduction and maintenance of weight loss. It reduces food intake and attenuates the fall in metabolic rate associated with weight loss.

Objective: To review the metabolic effects associated with sibutramine use.

Methods: Relevant articles were identified through a Medline search (up to December 2004).

Results: Weight loss with sibutramine treatment is associated with improved insulin sensitivity and a fall in glycosylated haemoglobin levels in type 2 diabetic patients. In most trials sibutramine exerted favourable effects on lipids, especially on high density lipoprotein (HDL) cholesterol and triglycerides, as well as on the total:HDL cholesterol ratio. Sibutramine also lowers serum uric acid concentrations. Furthermore, this drug seems to favourably influence adipocytokines; it reduces serum leptin and resistin levels and increases adiponectin levels. Sibutramine also exerts a beneficial effect on hyperandrogenaemia in obese women with polycystic ovary syndrome. Preliminary findings also suggest that weight loss following treatment with sibutramine is useful in patients with non-alcoholic fatty liver disease (NAFLD).

Conclusion: Weight loss following sibutramine administration is associated with several favourable metabolic effects.     

The utility of animal models to evaluate novel anti-obesity agents

The global incidence of obesity continues to rise and is a major driver of morbidity and mortality through cardiovascular and cerebrovascular diseases. Animal models used in the discovery of novel treatments for obesity range from straightforward measures of food intake in lean rodents to long-term studies in animals exhibiting obesity due to the continuous access to diets high in fat. The utility of these animal models can be extended to determine, for example, that weight loss is due to fat loss and/or assess whether beneficial changes in key plasma parameters (e.g. insulin) are evident. In addition, behavioural models such as the behavioural satiety sequence can be used to confirm that a drug treatment has a selective effect on food intake. Typically, animal models have excellent predictive validity whereby drug-induced weight loss in rodents subsequently translates to weight loss in man. However, despite this, at the time of writing orlistat (Europe; USA) remains the only drug currently marketed for the treatment of obesity, with sibutramine having recently been withdrawn from sale globally due to the increased incidence of serious, non-fatal cardiovascular events. While the utility of rodent models in predicting clinical weight loss is detailed, the review also discusses whether animals can be used to predict adverse events such as those seen with recent anti-obesity drugs in the clinic.     

Current concepts in the pharmacological management of obesity.

The pharmacological management of obesity has gained increasing attention as new weight loss treatments are approved and a significant proportion of the public strives to lose weight. Obesity is associated with a high mortality rate, multiple chronic medical conditions, and carries an enormous financial burden. Obesity is a multifactorial condition, most often due to an imbalance in energy intake and expenditure. Despite the greater focus on management of obesity, weight loss remains a difficult goal to achieve. Obesity is a chronic medical condition that may require long term treatment, therefore the risks and benefits of all pharmacological agents must be carefully considered. Noradrenergic appetite suppressants (ie. phenyl-propanolamine, phentermine) result in weight loss but stimulatory effects limit their use. The serotonergic agents (fenfluramine, dexfenfluramine) were effective weight loss drugs, but were voluntarily withdrawn from the US market last year because of cardiovascular and pulmonary complications. The combination noradrenergic/serotonergic agent sibutramine is indicated for the management of obesity, particularly in the presence of other cardiovascular risk factors. Modest weight loss is achieved with sibutramine, although weight gain is significant after discontinuation. In addition, long term safety data are not yet available. The thermogenic combination of ephedrine plus caffeine is minimally effective, and adverse effects are usually transient. Other thermogenic agents, such as beta3-agonists, are still under investigation. Agents may alter digestion through lipase inhibition (orlistat) or fat substitution (olestra). Orlistat decreases systemic absorption of dietary fat, decreasing body weight and cholesterol. Olestra is a fat substitute that has been incorporated into snack foods. Olestra substitution for dietary fat has not been studied as a weight loss strategy, although olestra has no caloric value and may be beneficial. The use of orlistat and olestra may be limited by gastrointestinal adverse effects. Finally, the manipulation of leptin and neuropeptide Y are under investigation for the treatment of obesity. Pharmacological agents should be used as an aid to a structured diet and exercise regimen in the treatment of obesity. Weight loss agents may result in initial weight loss, but sustained weight loss is not always achieved even with continuation of treatment. The effect of weight loss obtained while using pharmacotherapeutic agents on morbidity and mortality has not been established. Therefore, diet and exercise should be the focus of any weight loss programme. There is a continued need for safe and effective pharmacotherapeutic agents for the treatment of obesity.     

Anorexic effect of (R)-sibutramine: comparison with (RS)-sibutramine [corrected] and (S)-sibutramine

Sibutramine is one of the very few drugs that are approved for long-term treatment of obesity. Sibutramine is a racemic mixture (RS) containing two equal forms of the R(+) and S(-) enantiomers. In this paper, we have investigated comparative anorexic effect of sibutramine enantiomers and their recemate form in rats. After obtaining two days of baseline results, rats were administered orally either with (RS)-sibutramine or its enantiomers (R)- or (S)-sibutramine at dose levels of 5, 10, 20 mg/kg each for 4 days and body weight, food intake and water intake were measured daily. Locomotor activity score of each rat was also recorded on each day. R-Sibutramine and (RS)-sibutramine produced dose dependant decrease in the body weight and food intake. On the other hand, (S)-sibutramine was shown to increase in these parameters. Neither sibutramine nor it's enantiomers showed any consistent effects on spontaneous motor activity (SMA) scores. In conclusion, (R)-sibutramine is better anorexic than or (RS)-sibutramine or it's (S)-enantiomers.     

盐酸西布曲明治疗单纯性肥胖的疗效与安全性观察

目的 评价盐酸西布曲明治疗单纯性肥胖的疗效与安全性。方法用多中心、随机、双盲、平行、安慰剂对照的研究方法,共观察240例,中途退出29例,全部完成例数为211例,其中治疗组103例,对照组108例,随机分为2组,清洗期7～10天,口服盐酸西布曲明片每天1 0 mg或安慰剂每天1片共1 2周,观察体重变化,并进行临床和实验室检查。结果从第2周起,治疗组体重降低大干安慰剂组,至1 2周,治疗组体重平均降低3.28 kg,安慰剂组0.25 kg,治疗组药物不良反应主要有口干、心率增快、便秘等,但症状轻,大部分能耐受。结论 盐酸西布曲明治疗单纯性肥胖有效且较安全。     

西布曲明对比奥利司他治疗肥胖症的Meta分析

目的：系统评价西布曲明与奥利司他治疗肥胖症的临床疗效及其临床应用价值。方法：计算机检索PubMed、EMBASE、SCI、CochraneLi-brary、中国生物医学文献数据库、中文科技期刊全文数据库、中国期刊全文数据库及中华医学会数字化期刊,收集西布曲明与奥利司他治疗肥胖症的随机对照试验,检索时间截至2009年12月。采用Cochrane系统评价员手册文献质量评价标准评价纳入研究质量,用RevMan5.0软件进行Meta分析。结果：共纳入5个随机对照试验,研究地点均在国外。Meta分析结果显示：在体重减轻、体重指数（BMI）降低、腰围减少、低密度脂蛋白降低的比较上,西布曲明组与奥利司他组均有明显的减肥效果,但两药减肥效果无差异。两组间不良反应较少,但由于药物作用机制不同,不良反应的表现不同。结论：西布曲明与奥利司他在治疗肥胖上有显著疗效,两者间无明显差异,同时两组药物间不良反应表现不同。     

Orlistat: new preparation. No hurry . .

(1) Treatments for obesity are disappointing. None has yet shown an effect on morbidity and mortality. Non drug treatments are poorly assessed. Stable long-term weight loss necessitates long-term management. (2) Orlistat, a gastrointestinal lipase inhibitor, is indicated, in combination with a low-calorie diet, for the management of obesity. (3) The assessment file is rather bulky and methodologically sound, at least in terms of the "weight loss" end point. (4) During medium-term trials (12-24 months), orlistat administered at a dose of 120 mg three times a day and combined with dietary intervention had a moderate positive impact on body weight (-3.5 kg on average). (5) No longer-term trials have been done. (6) It is not known whether this drug affects morbidity and mortality linked to obesity. (7) In clinical trials there was an increase in the frequency of breast cancer among patients treated with orlistat. This potential risk is currently being assessed in a specific trial. (8) Gastrointestinal adverse effects are frequent. (9) Treatment is costly.