orlistat, Xenical, alli
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
GENERIC NAME: orlistat
BRAND NAME: Xenical, alli
DRUG CLASS AND MECHANISM: Orlistat is a drug that promotes loss of weight by preventing the digestion and absorption of fat in food. In the intestine, an enzyme called lipase (produced primarily by the pancreas) breaks apart fat in food so that it can be absorbed into the body. Orlistat blocks the action of lipase and thereby prevents the breakup and absorption of fat. Orlistat blocks absorption of about 25% of the fat in a meal. The unabsorbed fat is excreted in the stool. The FDA approved Orlistat by prescription in 1999. alli, a lower dose formulation of orlistat, was approved for purchase without a prescription "over the counter" in 2007.
PRESCRIPTION: Orlistat yes, alli no
GENERIC AVAILABLE: No
PREPARATIONS: Capsules: 60 mg (alli), 120 mg (Xenical)
STORAGE: Capsules should be stored at room temperature, 15-30 C (59-86 F)
PRESCRIBED FOR: Orlistat is combined with a reduced-calorie diet to promote weight loss. Orlistat also may be used to prevent weight gain after weight has been lost. Candidates for treatment with orlistat are patients who are obese with a body mass index (a measure of obesity) of more than 30 kg/m2. Candidates also include patients with a body mass index of between 27 and 30 kg/m2 if other risk factors for arteriosclerosis are present such as high blood pressure, diabetes, and elevated blood cholesterol or triglycerides. Based on several scientific studies, the average weight loss that is achieved when orlistat is taken as recommended for six months to one year is 12.4 to 13.4 pounds.
DOSING: The recommended prescription dose for Xenical is one capsule (120 mg) three times daily. The recommended dose for alli is 60 mg three times daily. Orlistat should be taken one hour after or during a meal containing about 15 mg of fat. Meals without fat do not require orlistat. No additional benefit has been shown when orlistat was taken in doses greater than 120 mg. Patients should eat a nutritionally balanced, reduced calorie diet that contains approximately 30% of calories from fat. alli includes an individually tailored online weight loss support program.
Some dietary vitamins bind to fat (vitamins A, D, E and beta- carotene). When orlistat is taken, these vitamins are not absorbed and are eliminated in the stool in increased amounts along with the fat. Therefore, patients taking orlistat should take a multivitamin containing these "fat-soluble" vitamins to ensure that adequate amounts of the vitamins are available for absorption. To ensure that the vitamins in the multivitamins are not bound to fat like the vitamins in the diet, the multivitamin should be taken at least two hours before or several hours after the orlistat.
DRUG INTERACTIONS: The blood thinning effect of warfarin (Coumadin) depends on the amount of vitamin K in the body, and vitamin K is one of the vitamins that binds to fat. Patients receiving warfarin who begin orlistat should have their blood clotting monitored closely because the orlistat may cause levels of vitamin K to decline. This will increase the effects of warfarin and lead to abnormal bleeding from the warfarin. There is no evidence that a deficiency of vitamin K occurs in patients who are taking orlistat.
Orlistat may reduce the absorption and blood levels of cyclosporine (Sandimmune) when both drugs are administered together. Therefore, cyclosporine should be administered two hours before or after orlistat, and more frequent monitoring of cyclosporine levels may be needed.
Hypothyroidism has been reported when orlistat and levothyroxine (Synthroid, Levoxyl, Levothroid, Unithroid) were combined. Patients treated with both orlistat and levothyroxine should be monitored for changes in thyroid function. The orlistat and levothyroxine should be taken at least four hours apart.
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