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Xenical (Orlistat) - Summary



XENICAL (orlistat) is a gastrointestinal lipase inhibitor for obesity management that acts by inhibiting the absorption of dietary fats. Orlistat is (S)-2-formylamino-4-methyl-pentanoic acid (S)-1-[[(2S, 3S)-3-hexyl-4-oxo-2-oxetanyl] methyl]-dodecyl ester.

XENICAL is indicated for obesity management including weight loss and weight maintenance when used in conjunction with a reduced-calorie diet. XENICAL is also indicated to reduce the risk for weight regain after prior weight loss. XENICAL is indicated for obese patients with an initial body mass index (BMI) ≥30 kg/m2 or ≥27 kg/m2 in the presence of other risk factors (e.g., hypertension, diabetes, dyslipidemia).

Table 1 illustrates body mass index (BMI) according to a variety of weights and heights. The BMI is calculated by dividing weight in kilograms by height in meters squared. For example, a person who weighs 180 lbs and is 5 ' 5 " would have a BMI of 30.

Table 1 Body Mass Index (BMI), kg/m2 1

1 Conversion Factors:
Weight in lbs ÷ 2.2 = weight in kilograms (kg)
Height in inches × 0.0254 = height in meters (m)
1 foot = 12 inches

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Published Studies Related to Xenical (Orlistat)

Orlistat 60 mg reduces visceral adipose tissue: a 24-week randomized, placebo-controlled, multicenter trial. [2011.09]
It is well established that abdominal obesity or upper body fat distribution is associated with increased risk of metabolic and cardiovascular disease. The purpose of the present study was to determine if a 24 week weight loss program with orlistat 60 mg in overweight subjects would produce a greater change in visceral adipose tissue (VAT) as measured by computed tomography (CT) scan, compared to placebo...

Systematic review of the clinical efficacy of sibutramine and orlistat in weigth loss, quality of life and its adverse effects in obese adolescents. [2011.06]
INTRODUCTION: The prevalence of obesity, a serious public health problem, is increasing among teenagers and thus also increases cardiovascular morbidity and mortality in adulthood. OBJECTIVE: To provide a systematic review of the best evidence about the effect of sibutramine and orlistat in weight loss, quality of life and its adverse effects in adolescents diagnosed with obesity... CONCLUSIONS: Sibutramine and orlistat in combination with a hypocaloric diet and changes in lifestyle in obese adolescents achieve a short-term loss of weight greater than that achieved through the dietary-behavioral therapy alone.

Early weight loss and outcome at one year in obese adolescents treated with orlistat or placebo. [2011.04]
BACKGROUND: Pharmacotherapy, associated with a comprehensive weight loss intervention, has emerged as a promising therapeutic approach in adolescents. Identification of subjects who best respond to a pharmacological intervention remains difficult. OBJECTIVE: To compare the value of early weight loss after 12 weeks of treatment with placebo or orlistat (120 mg three times a day) in predicting treatment outcome after 52 weeks... CONCLUSIONS: Early weight loss predicts a favourable outcome in both placebo-treated and orlistat-treated subjects but is more than 2 times more likely to occur in the orlistat group. Addition of orlistat should be considered as part of a weight loss intervention but reevaluated after 3 months of treatment.

Orlistat in clozapine- or olanzapine-treated patients with overweight or obesity: a 16-week open-label extension phase and both phases of a randomized controlled trial. [2011.03]
CONCLUSIONS: In clozapine- or olanzapine-treated overweight or obese patients able to take orlistat on a long-term basis, the drug, with no concomitant hypocaloric diet or behavioral interventions, caused moderate weight loss only in men. However, some metabolic benefits may be achieved independently of weight changes. In patients who do not respond to orlistat within the first 16 weeks, continuation treatment may provide no additional benefits. TRIAL REGISTRATION: controlled-trials.com Identifier: ISRCTN65731856. (c) Copyright 2011 Physicians Postgraduate Press, Inc.

Effects of short-term treatment with orlistat on growth hormone/insulin-like growth factor-I axis in obese post-menopausal women. [2011.02]
AIM: Obesity is associated with an altered GH/IGF-I axis status, accounting for the increased cardiovascular risk in obese subjects with GH deficiency. Aim of this randomized, simple-blind, cross-over study was to verify the effectiveness of a short-term treatment with orlistat in reducing non-esterified fatty acid (NEFA) and influencing the endogenous activity of GH/IGF-I axis in obese subjects. OUTCOME MEASURES: The primary outcome measures were post-prandial lipemia; GH peak after GHRH+arginine; IGF-I; IGF-binding protein (BP)-3, IGF-I/IGFBP-3 ratio. Secondary outcome measures were insulin resistance (IR) indexes (homeostasis model assessment of insulin resistance and Insulin Sensitivity Index)... CONCLUSIONS: Orlistat is effective in inducing a weight-independent higher reduction in post-prandial NEFA levels than dietary treatment alone along with increase in GH peak, IGF-I levels, and IGFI/ IGFBP-3 ratio. These results might add a new potential benefit of orlistat in the management of obese subjects.

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Clinical Trials Related to Xenical (Orlistat)

Study of Fat Malabsorption by Lipiblock Versus Xenical [Completed]
Obesity is a chronic condition with fat-rich diets playing a major role in its etiology. Pharmacological therapy has been proposed for weight loss and maintenance. This study aims to study the intestinal lipase blockade by partial inhibition of fat absorption after treatment with two commercials formulations of Orlistat.

Meta-analysis of Orlistat Laboratory Data From Placebo-controlled Clinical Trials [Completed]
Roche and GSK will carry out a meta-analysis of liver function data from trials of orlistat to establish whether there is any indication of liver toxicity. The motivation is a cumulative assessment of drug-induced liver injury (DILI) conducted by the FDA following spontaneous reports of liver toxicity in people taking Xenical or Alli.

Study for the Treatment of Significant Steatosis With Xenical Followed by Treatment of Hepatitis C With Pegasys/Copegus [Completed]
This is a prospective, multi-center, randomized, placebo-controlled trial in subjects with histological evidence of > 33% hepatic steatosis or nonalcoholic steatohepatitis (NASH) and chronic hepatitis C. Patients who have not been previously treated for hepatitis C (treatment naive) will be enrolled.

Orlistat Induced Modulation on the Fatty Acid Composition in Obese Females [Completed]
Orlistat is a popular drug approved for long-term use which produces weight loss by inhibiting triglycerides, main components of fats in the diet and reducing dietary fat absorption by up to 30%. The effect of this drug on human blood fatty acid profile has not been described yet. The FA composition of RBCs, plasma and platelets can be used to monitor of many pathological processes. This study presents alteration of FA composition in RBCM and phospholipids, triglycerides and cholesteryl esters from plasma of health obese female volunteers treated with nutritional orientation and orlistat (120 mg t. i.d) for 3 months.

Safety and Efficacy of Xenical in Children and Adolescents With Obesity-Related Diseases [Completed]
Obesity is a condition affecting one-third off the U. S. population and is a major risk actor for the development of Type 2 diabetes, hyperlipidemia (increased levels of fat in the blood), hypertension (high blood pressure), and other disorders of the heart and lungs. Individuals with the onset of obesity during childhood or adolescence are at an increased risk of obesity-related, diseases, both during adolescence and later in adult life. African American girls and women are at an increased risk for obesity, and have substantial rates of obesity-related diseases and causes of death. Further, many African American adult women fail to respond to many of the therapeutic approaches used to treat obesity. At present there are no medical therapies proven effective for the correction of severe obesity in children or adolescents. One medication that may have a favorable risk-benefit ratio in pediatric populations is Orlistat (Xenical, Hoffmann LaRoche). Orlistat works by preventing the action of enzymes in the digestive process, interfering with the absorption of approximately 1/3 of the fat eaten in the diet. Xenical appears to be effective for reducing weight and obesity-associated diseases in obese adults. Researchers propose to determine the safety, tolerability, and efficacy of Xenical in 12-17 year old severely obese African American and Caucasian children and adolescents who have one or more obesity-related disease (hypertension, hyperlipidemia, sleep apnea, hepatic steatosis, insulin resistance, impaired glucose tolerance, or Type 2 diabetes).

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Reports of Suspected Xenical (Orlistat) Side Effects

Drug Ineffective (5)Diarrhoea (5)Pancreatic Carcinoma (4)Rectal Haemorrhage (4)Haematochezia (4)Insulin Resistance (4)Hepatic Siderosis (4)Chills (3)Pain (3)Liver Disorder (3)more >>


Based on a total of 11 ratings/reviews, Xenical has an overall score of 6.91. The effectiveness score is 6.73 and the side effect score is 7.27. The scores are on ten point scale: 10 - best, 1 - worst. Below are selected reviews: the highest, the median and the lowest rated.

Xenical review by 39 year old female patient

Overall rating:  
Effectiveness:   Highly Effective
Side effects:   Mild Side Effects
Treatment Info
Condition / reason:   Obesity
Dosage & duration:   120 mg taken 3 times daily, 1 at each meal for the period of 3 months
Other conditions:   High Cholesterol
Other drugs taken:   None.
Reported Results
Benefits:   Cholesterol went from 265 to 199. Lost 32 lbs. in 3 months.
Side effects:   One incident of an oily stool.
Comments:   I took part in a 3-month Obesity/Binge Eating study back in 2004 which included the use of a Placebo or Orlistat (Xenical) conducted by a local Hospital/Medical Center. I would meet with the doctor's weekly and was put on a low-fat diet and asked to do moderate exercise of 30-40 minutes 3 days a week during this study. At the time I was Age 39, 5 ft 7 and 200 lbs. and a cholesterol level of 265 (you had to have a BMI of 30 percent in order to participate in study, and I just made it per the weight and height chart). Half of the study participants were put on a placebo pill and half were put on Orlistat (Xenical). They did not tell the participants during the study if they had the placebo or if they had the Orlistat. At the end of the 3 month study, I lost 32 lbs. (down to 168 lbs.) and my cholesterol went from 265 to 199. I was told at that time I was taking Orlistat. The participants who took Orlistat lost more weight than the ones who took placebo and did the low-fat diet. I can only remember once having what may have been an oily stool. I never had cramps, diarrhea or any type of bowel accidents. It is now 2010, and I have put on 20 lbs. since. I am considering trying to get my family doctor to prescribe Orlistat. I have not heard anything negative about the medication, except for the side effects of oily stools, etc. I believe the people who have experienced the bad side effects are people who are continuing to eat fatty foods (such as pizza, cheeseburgers, etc.) and continue to take the Orlistat. If you follow the directions, you are to eat low-fat and also take a multi-vitamin. I look forward to trying out the Orlistat again. :)


Xenical review by 42 year old female patient

Overall rating:  
Effectiveness:   Considerably Effective
Side effects:   Moderate Side Effects
Treatment Info
Condition / reason:   weight loss
Dosage & duration:   120mg taken once a day for the period of when needed
Other conditions:   None
Other drugs taken:   None
Reported Results
Benefits:   Through use of the drug and the side effects its produced, I was made much more aware of the level of fat I was consuming with my meals and took measures to reduce the intake
Side effects:   Oil in stool
Comments:   I was to take one dose and a full glass of water at each of three meals per day. I came to find out that taking the drug once a day (with lunch) was effective enough to receive the benefits. It was rare that I took it twice a day and never three times a day.


Xenical review by 32 year old female patient

Overall rating:  
Effectiveness:   Marginally Effective
Side effects:   No Side Effects
Treatment Info
Condition / reason:   over weight
Dosage & duration:   120mg taken 2/3 times a day for the period of 1 year
Other conditions:   n/a
Other drugs taken:   inderal and wellbutrin
Reported Results
Benefits:   i have been on xenical for a little over 2 weeks and i lost 2 lbs and gained it back,i do not have oily stools infact i have a hard time going to the bathroom now.the only benefit i can see so far with xenical for me is i try to watch what i eat.
Side effects:   i dont have any other then now i am constipated
Comments:   n/a

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Page last updated: 2011-12-09

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