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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This review explains and surveys very recent findings and experimental results concerning molecular pathology and genetics of overweight and obesity and also evaluates their relevance for the actual treatment of obesity at present. Most of these studies were done on inbred obese mice or rats and it is yet unknown to what extent the results do apply to human overweight. Nevertheless these studies led to the discovery of a new hormone--OB-protein or leptin--produced by adipocytes of animals. It does not only increase satiety by influencing feeding centers and decrease body weight but it also interferes with several peripheral metabolic functions. Mutations of leptin expression or expression of leptin receptors as observed in animals are, however, very rare in humans. In obese individuals (and animals) there is a yet unexplained resistance to the effects of leptin which interferes with successful therapeutic use of leptin in human obesity. Various other recently discovered transmitters modifying feeding habits may, however, become targets of future drugs making dietary weight loss and its maintenance more acceptable and successful. At present obese people and patients have to rely, however, on traditional methods of weight loss though these are known to yield poor results over prolonged periods of time. Orlistat, a recently introduced drug results in malabsorption of fat from the gut by inhibiting lipases. Though it is not based on recent insights to regulation of body weight it is promising primarily for educating patients to reduce their nutritional fat intake.
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PMID:[New knowledge about obesity--news for obese patients?]. 987 83

Obesity is an increasing health problem in most developed countries and its prevalence is also increasing in developing countries. There has been no great success with dietary means and life style modification for permanent weight loss. Various surgical treatment methods for obesity are now available. They are aimed at limiting oral energy intake with or without causing dumping or inducing selective maldigestion and malabsorption. Based on current literature, up to 75% of excess weight is lost by surgical treatment with concomitant disappearance of hyperlipidaemias, type 2 diabetes, hypertension or sleep apnoea. The main indication for operative treatment is morbid obesity (body mass index greater than 40 kg/m2) or severe obesity (body mass index > 35 kg/m2) with comorbidities of obesity. Orlistat is a new inhibitor of pancreatic lipase enzyme. At doses of 120 mg three times per day with meals it results in a 30% reduction in dietary fat absorption, which equals approximately 200 kcal daily energy deficit. In the long term, orlistat has been shown to be more effective than placebo in reducing body weight and serum total and low-density lipoprotein cholesterol levels. Orlistat has a lowering effect on serum cholesterol independent of weight loss. Along with weight loss, orlistat also favourably affects blood pressure and glucose and insulin levels in obese individuals and in obese type 2 diabetic patients.
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PMID:New aspects in the management of obesity: operation and the impact of lipase inhibitors. 1009 83

The prevalence of obesity has doubled in the last 10 years and is now reaching epidemic proportions. There is a significant comorbidity and financial cost associated with this disorder. Orlistat is an intestinal lipase inhibitor that is approved for the treatment of obesity. Recent randomized, double-blind, placebo-controlled trials have demonstrated the benefit of orlistat used in conjunction with a hypocaloric (low-fat) diet in facilitating weight reduction and the long-term maintenance of this weight loss. Patients treated with orlistat lost a greater amount of initial body weight compared to those who received placebo. After 24 months of treatment, weight loss of more than 5% was maintained in a greater number of those treated with orlistat. This was associated with significant reductions in cardiovascular risk factors (cholesterol, LDL cholesterol, LDL:HDL cholesterol ratio). The main adverse events are related to fat malabsorption, with potential losses of fat-soluble vitamins and other compounds. Orlistat as a treatment for obesity, when prescribed within present guidelines, can aid modest weight loss in about one-third of patients. More importantly, it can assist in the maintenance of weight loss with major medical benefits for these patients.
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PMID:Review article: malnutrition and maltreatment--a comment on orlistat for the treatment of obesity. 1046 73

Orlistat (Xenical, Hoffmann-La Roche) is a powerful inhibitor of gastrointestinal lipase and as such, reduces fat absorption. Unlike other weight-reducing drugs it is minimally absorbed and has no effects in the CNS. Orlistat is indicated for patients with a body mass index (BMI) of at least 30 kg/m2 or 28 kg/m2 in the presence of obesity-associated complications, such as hypertension, diabetes mellitus, hyperlipidaemia and obstructive sleep apnoea. In clinical trials, orlistat (120 mg t.i.d.) in combination with life-style modification and a hypocaloric diet (30% of energy from fat) induced significantly more weight loss and improved health complications of obesity (diabetes, hypertension, hyperlipidaemia) compared to patients treated with diet alone. Side effects related to fat malabsorption, occurred in more than 20% of subjects during the first year of treatment and included oily faecal spotting, abdominal pain, flatus with discharge and fatty/oily stool. Side effects from orlistat diminished in the second year of treatment. Plasma concentrations of fat soluble vitamins decreased in orlistat-treated patients but did not usually fall below the normal range. No studies have evaluated the efficacy of orlistat or side effect profile beyond two years.
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PMID:Orlistat in the treatment of obesity. 2694 9

Orlistat, a potent gastrointestinal lipase inhibitor, is a member of a new class of drugs designed for the long-term treatment of obesity. When given with a fat-containing meal, orlistat reduces dietary fat absorption by approximately 30%, which equates to a decrease in caloric absorption of approximately 200 kilocalories per day. A 2-year European study found a mean decrease in body weight of 10.2% (10.3 kg) in the orlistat group compared to 6.1% (6.1 kg) in the placebo group at 1 year. Additionally, 9.3% of the orlistat group versus 2.1% of the placebo group lost >20% of their initial weight. Serum lipids and diabetes control are also improved by orlistat. Related to orlistat's mechanism of action, side effects include oily spotting, flatulence and frequent loose stools, but not frank diarrhea or intestinal malabsorption. Vitamin D and beta-carotene levels decreased, but remained within the normal range. In summary, orlistat is the first example of a new class of antiobesity drugs that enhances weight loss and weight maintenance by interfering with dietary fat absorption. Orlistat has tolerable gastrointestinal side effects and no major drug toxicity. Orlistat is a viable adjunct to lifestyle interventions used in the long-term management of obesity.
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PMID:Orlistat for the long-term treatment of obesity. 1297 16

Orlistat is a specific inhibitor of pancreatic and gastric lipases leading to decreased absorption of fat. In the present study, we measured the effect of orlistat on lymphatic fat transport in rats following intake of oils very different in FA composition and TAG structure, and compared this with the transport in normal rats and rats with fat malabsorption. Rats were subjected to cannulation of the main mesenteric lymph duct, and a feeding catheter was inserted into the stomach. In addition, malabsorbing rats were cannulated in the common bile and pancreatic duct. Emulsified safflower, fish, and randomized oils were administered, and lymph was collected for 24 h and analyzed for FA composition. Administration of 25 mg orlistat together with the dietary oils resulted in very small changes from baseline lymphatic transport, indicating that inhibition of the fat absorption was almost complete and furthermore that the source of fat had no influence on the inhibitory effect of orlistat. Orlistat did not interfere with the absorption of the hydrolysis products, since high absorption of sn-2 MAG and FFA (oleic acid) mixed with orlistat was observed. The baseline lymphatic transport in the orlistat group was higher than in the malabsorbing group, but this was the result of generally lower transport of endogenous FA in the malabsorbing group, presumably caused by the absence of bile FA. The transport of FA in normal rats was several-fold higher than the transport after orlistat addition and in malabsorbing rats. Thus, this study showed that orlistat inhibited fat hydrolysis, and thereby lymphatic absorption, almost completely independently of the fat administered.
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PMID:Effect of orlistat on fat absorption in rats: a comparison of normal rats and rats with diverted bile and pancreatic juice. 1466 68

Dietary modification is useful in both type 1 and type 2 diabetes. Glucose levels after a meal are largely determined by carbohydrate intake. Decreased intake of simple carbohydrates and increased fiber consumption lower postprandial glucose. Obesity has become epidemic in the United States and has dramatically increased the incidence of type 2 diabetes by augmenting insulin resistance. Dietary treatment of obesity has been frustrating. Success will require education in using foods with high fiber contents, low glycemic indexes, and low saturated fat levels. The use of natural foods must be supplemented by the use of semisynthetic foods with desirable properties. The educational efforts required are substantial and must be recognized by third-party reimbursement agencies. Operative procedures to decrease intake or reduce the absorption of food are being used with increasing frequency. Bariatric surgery is often successful in inducing a substantial loss of weight; however, this success must be balanced against the complications of surgery, which can be considerable. The pharmacologic approaches to treatment of obesity have focused primarily on anorexigenic agents. Several polypeptides that induce satiety are currently under study, including leptin and glucagon-like peptide-1 (GLP-1). Orlistat has been used to induce the malabsorption of fat to reduce caloric ingestion. Of the currently used oral hypoglycemics, metformin and the disaccharidase inhibitors have the best tendency to promote weight loss. There is active research on the uncoupling proteins that induce thermogenesis and promote the dissipation of calories. The beta-3 agonists act through the uncoupling proteins. The thiazolidinediones tend to promote weight gain through the PPAR gene locus. Agents that antagonize this effect could induce weight loss. The future will undoubtedly bring us drugs that are effective in causing weight loss. The advent of drugs to successfully combat obesity will substantially improve public health.
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PMID:Advances in diabetes for the millennium: nutritional therapy of type 2 diabetes. 1564 15

Orlistat is an oral inhibitor of gastrointestinal lipase used for weight reduction in obese patients. Although most adverse drug effects manifest in the gastrointestinal tract, this is the first reported case of orlistat-induced acute kidney injury secondary to acute oxalate nephropathy in a white woman with underlying chronic kidney disease. Acute kidney injury was associated temporally with an increased dose of orlistat and the development of increased fat malabsorption (more frequent loose oily stools). Urine sediment showed abundant calcium oxalate crystals and increased 24-hour urine oxalate concentration. Kidney biopsy showed deposition of calcium oxalate crystals within tubular lumens, consistent with acute oxalate nephropathy. Orlistat therapy was discontinued, and oral fluid intake was increased. A second kidney biopsy performed 1 month later to evaluate the slow resolution of kidney failure did not show calcium oxalate crystals within tubules. A steady improvement in renal function subsequently was observed. Results of a repeated 24-hour urine oxalate collection performed 3 weeks later when kidney function had improved were within normal limits.
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PMID:Acute oxalate nephropathy associated with orlistat, a gastrointestinal lipase inhibitor. 1718 56

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.
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PMID:Orlistat-associated adverse effects and drug interactions: a critical review. 1809 46

Obesity is reaching epidemic proportions worldwide and it is correlated with various comorbidities, among which the most relevant are diabetes mellitus, arterial hypertension, and cardiovascular diseases. Obesity management is a modern challenge because of the rapid evolution of unfavorable lifestyles and unfortunately there are no effective treatments applicable to the large majority of obese/overweight people. The current medical attitude is to treat the complications of obesity (e.g. dyslipidemia, hypertension, diabetes, and cardiovascular diseases). However, the potential of treating obesity is enormous, bearing in mind that a volitional weight loss of 10 kg is associated with important risk factor improvement: blood pressure -10 mmHg, total cholesterol -10%, LDL cholesterol -15%, triglycerides -30%, fasting glucose -50%, HDL cholesterol +8%. Drug treatment for obesity is an evolving branch of pharmacology, burdened by severe side effects and consequences of the early drugs, withdrawn from the market, and challenged by the lack of long-term data on the effect of medications on obesity-related morbidity and mortality, first of all cardiovascular diseases. In Europe three antiobesity drugs are currently licensed: sibutramine, orlistat, and rimonabant; important trials with clinical endpoints are ongoing for sibutramine and rimonabant. While waiting for their results, it is convenient to evaluate these drugs for their effects on body weight and cardiometabolic risk factors. Sibutramine is a centrally acting serotonin/noradrenaline reuptake inhibitor that mainly increases satiety. At the level of brown adipose tissue, sibutramine can also facilitate energy expenditure by increasing thermogenesis. The long-term studies (five) documented a mean differential weight reduction of 4.45 kg for sibutramine vs placebo. Considering the principal studies, attrition rate was 43%. This drug not only reduces body weight and waist circumference, but it decreases triglycerides and uric acid as well and it increases HDL cholesterol; in diabetics it improves glycated hemoglobin. Sibutramine has conflicting effects on blood pressure: in some studies there was a minimal decrease, in some others a modest increase. In all the studies this drug increased pulse rate. Sibutramine is not recommended in patients with uncontrolled hypertension, or in case of history of cardio- and cerebrovascular disease. Orlistat is a pancreatic lipase inhibitor that reduces fat absorption by partially blocking the hydrolysis of dietary triglycerides. A recent meta-analysis evaluated 22 studies lasting for at least 12 months, in obese patients with a mean body mass index of 36.7 kg/m2, where orlistat was associated with hypocaloric diet or behavioral interventions: the net average weight loss was 2.89 kg (confidence interval 2.27-3.51 kg). Considering the principal studies, attrition rate ranged from 33 to 57%. Orlistat significantly decreases waist circumference, blood pressure, total and LDL cholesterol, but has no effect on HDL and triglycerides. This drug significantly reduced the incidence of diabetes only in subjects with impaired glucose tolerance. The major adverse effects with orlistat are mainly gastrointestinal (fatty and oily stool, fecal urgency, oily spotting, fecal incontinence) and attenuate over time. Orlistat should be avoided in patients with chronic malabsorption and cholestasis. Rimonabant is a selective antagonist of cannabinoid type 1 receptor. This drug, by inhibiting the overactivation of the endocannabinoid system, produces anorectic stimuli at the central nervous level, but also has effects on the peripheral systems involved in metabolism control, such as liver, adipose tissue, skeletal muscles, endocrine pancreas, and gastrointestinal apparatus, influencing many processes partially unknown. An ample experimental program named RIO (Rimonabant In Obesity) involved about 6600 obese or overweight patients to identify the effects of rimonabant in weight loss and associated cardiometabolic abnormalities, over and beyond a caloric restriction of 600 kcal in the treatment and placebo arms. In the four double-blind RIO trials published (Rio-North America, RIO-Europe, RIO-Lipids, RIO-Diabetes), rimonabant 20 mg significantly (p <0.001) reduced weight by 6.3-6.9 kg in the non-diabetic groups vs placebo (-1.5-1.8 kg), whereas in the diabetic subjects enrolled in RIO-Diabetes, weight loss was 5.3 vs 1.4 kg in the placebo group. Attrition rate at 1 year ranged between 40 and 50%, similar to the studies with sibutramine or orlistat. Similarly to weight loss, also waist circumference was significantly reduced by rimonabant. As for cardiometabolic parameters, rimonabant induced a significant increase in HDL cholesterol and a significant decrease in triglycerides. Even if no significant LDL reduction was achieved, the RIO-Lipids study showed a significant decrease in small dense LDL particles, more atherogenic, in rimonabant-treated subjects. Non-diabetic treated patients improved basal insulin and indirect indexes of insulin resistance, while in the RIO-Diabetes study, the only one including diabetics, glycated hemoglobin improved by 0.7% in the active treatment arm vs placebo. The effects on HDL cholesterol and glycated hemoglobin seem in a large percentage unrelated to weight loss. These effects have been confirmed by another trial, named SERENADE, evaluating the treatment in naive diabetic patients. Rimonabant is not recommended in patients with a history of depressive disorders or suicidal ideation and with uncontrolled psychiatric illness, and is contraindicated in patients with ongoing major depression or ongoing antidepressive treatment. In conclusion, despite an enormous advancement in basic research to understand the pathogenetic mechanisms at the base of obesity, the pharmacological research did not reach the therapeutic opportunities available for other chronic conditions, like hypertension and dyslipidemia. However, the few molecules available for clinical practice (sibutramine, orlistat, rimonabant) have shown, when properly used, to contribute to reduce body weight and undoubtedly improve cardiometabolic risk factors. With this preamble, according to current guidelines and pharmacoeconomic studies, patients who might benefit from antiobesity treatment are those with a body mass index > or =30 or 27-29.9 kg/m2 with major obesity-related comorbidities such as hypertension, diabetes, dyslipidemia, obstructive sleep apnea, and metabolic syndrome.
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PMID:[Pharmacological therapy of obesity]. 1877 55


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