How Orlistat Works
Orlistat (Xenical, Alli) is a drug created for treating obesity. It was developed later than similar medications. It’s been approved for use in the USA since 1999.
Orlistat is the first weight loss medicine that doesn’t work systematically. It’s effective in the gastrointestinal tract only. It belongs to the group of pentanoic acid esters and forms covalent bonds with the active sites of serine residues in gastric and pancreatic lipases by inhibiting their activity and preventing the absorption of approximately 30% of fats our body gets from food. Weight loss is achieved due to these two factors:
- Reduction in fat intake;
- Side effects caused by the drug: unpleasant and uncomfortable feelings in the gastrointestinal tract that make patients avoiding high fat food.
When you are following a 2000 calories diet plan made up of 30% fat, Orlistat blocks the digestion of 22 grams of fat which equals the intake of 200 kcal a day. This helps you to eat 6000 less calories a month and reduce your body weight by nearly 900g. The second treatment factor motivates you to change your diet plan. When used properly, this medication can reduce your body weight even if the initial change in lifestyle proved to be ineffective.
The effectiveness of Orlistat in treating obesity has been proved by several randomized, placebo-controlled clinical trials each lasting for 1-2 years. Orlistat side effects were studied in two placebo-controlled trials. Patients were taking 120mg Orlistat 3 times a day. At first, all participants were following a low-calorie diet plan for 1 year. After that, they started to take either Orlistat or placebo for another year.
The research results were similar. The average weight loss was 10% when treated with Orlistat and 6% when treated with placebo. During the following year, patients who continued taking Orlistat increased their body weight by 1.5-3 kg and patients who kept taking placebo gained 4-6 kg (this body weight was close to the original). Besides, Orlistat has shown a positive change in the contents of total cholesterol, LDL, glucose, insulin and blood pressure levels. This drug was revealed to have a unique property. It affected the concentration of lipids in serum by inhibiting the absorption of fat in the digestive tract. Orlistat can be used for the correction of lipid levels.
Another study involved patients who suffered from both obesity and type 2 diabetes and were treated with sulfonylurea drugs. As statistics shows, Orlistat has significantly improved the plasma glucose levels and reduced the hemoglobin A1c, and lipids in the blood. It also helped to reduce the dose of sulfonylurea.
Orlistat Side Effects
alli diet capsules
For patient compliance with the treatment it is very important to control the severity of side effects. All patients who didn’t control the consumption of fats in their diet plan had a problem with oily loose stools. In about 20-40% cases Orlistat caused other side effects in the gastrointestinal tract, including frequent defecation, bloating, intense flatus, soiled clothes, peremptory urging to stool, and fecal incontinence. Thus it is very important to explain patients the rules of taking this drug and the importance of reducing the dietary fat content.
The most significant concerns of Orlistat therapy are big chances of malabsorption of fat-soluble vitamins A, D, E, K, B-carotene and other carotenoids. Indeed, Orlistat treatment decreased the amount of these substances in the plasma compared to placebo treatment. Still it remained within normal limits. Nonetheless, manufacturers recommend that all patients who take Orlistat should also take multivitamins with B-carotene and fat-soluble vitamins 2 hours before or after taking Orlistat.
Doctors usually prescribe their patients to take 120mg Orlistat (1 capsule) 3 times a day during fat meals. It is allowed to take the drug during or within 1 hour after a meal.
There is one more precaution that concerns Orlistat treatment. The caloric value of food is determined by 4 groups of substances: fats, carbohydrates, proteins, and alcohol. Orlistat partly prevents the absorption of only one of them. If a patient increases the intake of other substances instead of fats, the total caloric value of a diet plan also increases along with body weight. In order to make Orlistat treatment effective, it is necessary to pay attention at your diet plan and reduce its total caloric value.