orlistat

Orlistat is a lipase inhibitor used to aid weight loss and to treat obesity. It is marketed in prescription form as Xenical (120 mg) and in over-the-counter form as Alli (60 mg). Orlistat works by reversibly inhibiting pancreatic and gastric lipases in the gastrointestinal tract, reducing hydrolysis and absorption of dietary fats. In typical meals, fat absorption can be reduced by about one-third.

Indications and use: Orlistat is approved as an adjunct to a reduced-calorie diet for long-term weight management in adults and in some countries for adolescents aged 12 and older with overweight or obesity. It is not a substitute for diet and exercise and should be used as part of a comprehensive weight-management program. It is generally avoided during pregnancy.

Administration and dosing: The usual dose is 120 mg with each main meal containing fat. If a meal contains no fat, the dose should be skipped. If a planned meal contains fat but is skipped, skip that dose. For best results, it should be combined with a nutritionally balanced, reduced-calorie diet and physical activity.

Vitamin supplementation and drug interactions: Because orlistat reduces absorption of fat-soluble vitamins (A, D, E, K), patients are advised to take a multivitamin supplement at least two hours before or after dosing. Orlistat can affect the absorption of certain medications, including cyclosporine and levothyroxine; separate administration times as advised by a clinician. In rare cases, liver-related adverse events have been reported.

Adverse effects: The most common adverse effects are gastrointestinal and include oily stools, flatulence with discharge, fecal urgency, and frequent bowel movements, particularly with higher-fat meals. Serious liver injury is rare but possible; report symptoms such as jaundice or dark urine.