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 BRAND NAMES
- Europe: Xenical summary for the public
- International: Xenical
- Italy: Alli, Xenical
- US: Xenical PI, Patient information
 MECHANISM OF ACTION
Orlistat, is an anti-obesity medicine, which does not affect appetite.
Orlistat is a reversible inhibitor of gastrointestinal lipases (enzymes that digest fat).It exerts its therapeutic activity in the lumen of the stomach and small intestine by forming a covalent bond with the active serine residue site of gastric and pancreatic lipases.
When these enzymes are blocked, they cannot hydrolyse dietary fat, in the form of triglycerides, into absorbable free fatty acids and monoglycerides. This allows about 30% of the fat eaten in the meal to pass through the gut undigested. The body cannot use this dietary fat for energy or convert it into fat tissue. This helps weight reduction.
Patients taking 120 mg of orlistat three times a day had an average fall of 6.1 kg in body weight after a year, compared with 2.6 kg in those taking placebo.
Orlistat is indicated for obesity management including weight loss and weight maintenance in patients with a body mass index (BMI) of 30 or greater, or a BMI of 27 or greater and have other risk factors, such as high blood pressure, high cholesterol, heart disease or diabetes. Orlistat should be used in conjunction with a reduced-calorie diet.
One capsule (120 mg) taken with water just before, during, or up to one hour after each main meal that contains fat (up to three times a day).
Doses above 120 mg three times daily have not been shown to provide an additional weight-loss benefit.
Treatment with Orlistat should be stopped after 12 weeks if patients have been unable to lose at least 5% of their body weight since the start of treatment.
- Pregnancy (a minimum weight gain, and no weight loss, is currently recommended for all pregnant women, including those who are already overweight or obese)
- Chronic malabsorption syndrome
- Gallbladder problems (cholestasis)
- Hypersensitivity to Orlistat
 WARNINGS AND PRECAUTIONS
- Orlistat interferes with the absorption of the fat soluble vitamins (A, D, E and K). Take a multivitamin supplement that contains fat-soluble vitamins to ensure adequate nutrition. Multivitamin, should be taken at least 2 hours before or after taking Orlistat or at bedtime.
- Rare cases of severe liver injury with hepatocellular necrosis or acute hepatic failure have been reported
- Exclude organic causes of obesity (eg, hypothyroidism)
- When taken with a meal very high in fat, the possibility of gastrointestinal adverse reactions may increase (distribute the daily intake of fat over three main meals)
- Cyclosporine: A decrease in cyclosporine plasma levels has been observed in a drug-drug-interaction study. Take Orlistat and cyclosporine at least 3 hours apart.
- Levothyroxine: take Orlistat and levothyroxine at least 4 hours apart
- When warfarin or other anticoagulants are given in combination with orlistat, international normalised ratio (INR) values should be monitored
 PREGNANCY AND LACTATION
- Pregnancy Category X (US). Orlistat is contraindicated during pregnancy, because weight loss offers no potential benefit to a pregnant woman and may result in fetal harm. A minimum weight gain, and no weight loss, is currently recommended for all pregnant women, including those who are already overweight or obese, due to the obligatory weight gain that occurs in maternal tissues during pregnancy. No embryotoxicity or teratogenicity was seen in animals that received orlistat at doses much higher than the recommended human dose. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard of maternal weight loss to the fetus.
- Nursing Mothers: It is not known if Orlistat is present in human milk. Caution should be exercised if administered to a nursing woman.
 SIDE EFFECTS
Most common side effects of Orlistat include: Oily spotting, flatus with discharge, fecal urgency fatty/oily stool, oily evacuation, increased defecation and fecal incontinence.
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