Description Xenical (orlistat) is manufactured by Roche and is is a medicine to help you lose weight if your doctor has determined you are obese, or over weight with additional risk factors for obesity such as diabetes and/or elevated lipids. Find patient medical information for Xenical Oral on WebMD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. SIDE EFFECTS. Some people on alli™ (orlistat 60 mg) will experience GI side effects, which is expected since alli (orlistat 60 mg) works by inhibiting about 25% of dietary fat. alli (orlistat 60 mg) is half the strength of prescription Xenical® (orlistat 120 mg), and, as a result, has fewer GI events overall than Xenical®. Orlistat (120mg) is a generic prescription treatment that prevents 1/3 of dietary fat from being digested. It is cheaper than Xenical, but more expensive than Alli. Orlistat is used to help people lose weight and keep the weight off while eating a reduced-calorie diet. This medicine decreases the amount of fat that is absorbed from your diet. For Obesity I started taking Xenical (Orlistat) almost a week ago. Im 5.3 and currently weigh 162lbs. I gained about 30 pounds after 3 and a half years of using Mirena IUD thats why I started taking Orlistat because nothing was working, it seemed as if my metabolism had been shut. Orlistat reference guide for safe and effective use from the American Society of Health-System Pharmacists (AHFS DI). This diet plan is suitable for Orlistat users. Proper dieting while using Orlistat, can be twice as effective if you want to reach your weight loss goals. Orlistat (Xenical, alli) is a weight loss drug. Alli is available over-the-counter (OTC), and Xenical is available by prescription only. Side effects include abdominal cramping and pain, flatulence (farting), and fatty or oily stools. Drug interactions, dosage, and pregnancy and breastfeeding safety are provided. Orlistat works by inhibiting gastric and pancreatic lipases, the enzymes that break down triglycerides in the intestine. When lipase activity is blocked, triglycerides from the diet are not hydrolyzed into absorbable free fatty acids, and instead are excreted unchanged.