Find information on thousands of medical conditions and prescription drugs.

Orlistat

Orlistat (marketed as Xenical by Roche) is a drug designed to treat obesity. Its primary function is to prevent the absorption of dietary fats, thereby reducing caloric intake. It is intended for use in conjunction with a physician-supervised reduced calorie diet. more...

Home
Diseases
Medicines
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
Methoxsalen
OCL
Octabenzone
Octanoic acid
Octopamine
Octreotide
Ofloxacin
Ofloxacin
Olanzapine
Omeprazole
Oncovin
Ondansetron
Opium
Oratane
Oretic
Orinase
Orlistat
Ornidazole
Ornithine
Orotic acid
Orphenadrine
Ortho Evra
Oruvail
Ovcon
Ovral
Ovrette
Oxaliplatin
Oxamniquine
Oxandrin
Oxandrolone
Oxaprozin
Oxazepam
Oxcarbazepine
Oxetine
Oxibendazole
Oxiracetam
Oxprenolol
Oxybenzone
Oxybuprocaine
Oxycodone
Oxycodone
Oxymetazoline
Oxymetholone
Oxymorphone
Oxytetracycline
Oxytocin
P
Q
R
S
T
U
V
W
X
Y
Z

Pharmacology

Orlistat works by inhibiting pancreatic lipase, an enzyme that breaks down triglycerides in the intestine. Without this enzyme, triglycerides from the diet are prevented from being hydrolyzed into absorbable free fatty acids and are excreted undigested. Only trace amounts of orlistat are absorbed systemically, the primary effect is local lipase inhibition within the GI tract after an oral dose. The primary route of elimination is through the feces.

At the standard prescription dose of 120 mg three times daily before meals, orlistat prevents approximately 30% of dietary fat from being absorbed.

Efficacy

The amount of weight loss achieved with orlistat is variable. In 1 year clinical trials, between 35.5% and 54.8% of subjects achieved a 5% or greater decrease in body mass. Between 16.4% and 24.8% achieved at least a 10% decrease in body mass. A significant amount of subjects regained the weight after they stopped using orlistat. Despite this cosmetically small effect, there was a 37% reduction in the incidence of Type 2 diabetes, a significant difference.

Side effects

The primary side effects of the drug are GI-related. Side effects were most severe within the first year of therapy. Because its main effect is to prevent dietary fat from being absorbed, the fat is excreted unchanged in the feces and so the stool may become oily or loose. Increased flatulence is also common. Bowel movements may become frequent or urgent. Rare occurrence of fecal incontinence have been seen in clinical trials. To minimize these effects, foods with high fat content should be avoided.

The absorption of fat-soluble vitamins are inhibited by the use of orlistat. A multivitamin tablet containing these vitamins (D, E, A and beta-carotene) should be taken once a day, at least 2 hours before or after taking the drug.

Contraindications

Xenical is contraindicated in:

  • Malabsorption
  • Reduced gallbladder function (e.g. after cholecystectomy)
  • Pregnancy and breastfeeding
  • Certain kidney problems

Availability

In most areas orlistat is available by prescription only. In 2004, a lower-dose version of the drug (60 mg compared to 120 mg for the prescription version) was released over the counter in Australia and New Zealand; the United States is expected to follow in the near future.

On January 23, 2006, a US Food and Drug Administration advisory panel voted 11 to 3 to recommend the approval of an OTC formulation of orlistat (planned to be marketed under the name "Alli" by GlaxoSmithKline). The proposed product will consist of 60 mg dosage units, similar to the OTC products available elsewhere.

Read more at Wikipedia.org


[List your site here Free!]


Orlistat combined with metformin effective treatment in type 2 diabetes - Diabetes
From Nutrition Research Newsletter, 8/1/02

Effective weight management in individuals with type 2 diabetes is an essential component of treatment. Weight loss of 5 to 10% in obese and overweight individuals improves glycemic control and reduces the need for antidiabetic medication as well as lowers blood pressure, improves dyslipidemia, and is associated with a reduction in total and diabetic-related mortality. While it is difficult for overweight and obese individuals to loose and maintain weight loss, type 2 diabetics have even greater difficulty in maintaining weight loss. Unlike most diabetic pharmacotherapy that promotes weight gain, metformin produces minimal weight gain or slight weight loss and is suggested as oral therapy in overweight or obese type 2 diabetics. As traditional weight loss methods have failed there is an increase interest in pharmacologic weight loss interventions in patients with type 2 diabetes. The use of orlistat, a weight-loss medication that inhibits intestinal lipases, in combination with metformin has yet to be studied, although it can be hypothesized that the two together may work in combination to promote weight reduction.

The aim of a recent investigation of individuals with type 2 diabetes was to assess the efficacy and safety of orlistat plus a reduced-calorie diet in overweight and obese patients with metformin-treated disease. Diabetic subjects were eligible for the study if they were 40 to 65 years of age, had a BMI of 28 to 43 kg/[m.sup.2], had maintained a stable weight for at least three months, had Hb[A.sub.lc] between 7.5 and 12.0%, and had received metformin treatment at 1,000 to 2,550 mg/ day for at least six weeks. Sulfonylurea therapy in combination with metformin was allowed as long as the sulfonylurea dose was stable for 12 weeks prior to entering the study. Individuals receiving insulin, thiazolidinediones, or alpha-glucosidase inhibitors were excluded.

The multicenter, double-blind, randomized, placebo-controlled tiral was conducted at 34 centers in the United States and at six centers in Canada. The study consisted of a two-week screening phase followed by a 52-week treatment phase. Patients were randomized to one year of treatment with 120 mg orlistat or placebo three times daily with main meals. In order to ensure treatment group balance for initial glycemic control, patients were stratified into two groups based on Hb[A.sub.lc] levels. A reduced-calorie diet (~600 kcal daily deficit) was prescribed. The diet was based upon American Diabetes Association recommendations and contained 30% of calories as fat, 50% as carbohydrate, and 20% as protein. Patients received dietary counseling at baseline and at regular intervals throughout the study and were encouraged to increase their level of physical activity. Changes in body weight and Hb[A.sub.lc] were the primary efficacy variables. Fasting serum glucose and changes in diabetes medication were also used to assess efficacy. Other secondary efficacy variables were changes in serum lipids, blood pressure, and waist circumference at weeks 0, 24, and 52. All adverse events were recorded.

Following a year of treatment, mean weight loss was greater in the orlistat group than in the placebo group (-4.6% vs. -1.7% of baseline). Orlistat treatment also caused a greater improvement in glycemic control than placebo as evidenced by a greater reduction in serum Hb[A.sub.lc]. Additionally, when compared with placebo group, patients treated with orlistat had a greater decrease in total cholesterol, LDL cholesterol, and systolic blood pressure. More subjects treated with orlistat did experience gastrointestinal side effects, however more subjects in the placebo group withdrew prematurely from the study.

This data indicates that orlistat is a useful adjunctive therapy for promoting weight loss and improved glycemic control in obese and overweight individuals being treated with metformin for type 2 diabetes.

J. Miles, L. Leiter, P Hollander, et al. Effect of orlistat in overweight and obese patients with type 2 diabetes treated with metformin. Diabetes Care 25:1123-1128 (July, 2002). Correspondence: John M. Miles, MD, Division of Endocrinology and Metabolism, Mayo Clinic, 200 First ST. SW, Rochester, MN 55905. E-mail: miles.john@mayo.edu].

COPYRIGHT 2002 Frost & Sullivan
COPYRIGHT 2002 Gale Group

Return to Orlistat
Home Contact Resources Exchange Links ebay