title: The effect of orlistat, an inhibitor of dietary fat absorption, on the absorption of vitamins A and E in healthy volunteers.
abstract: An open-label, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers (between 20 and 44 years of age) to assess the effect of orlistat, a gastrointestinal lipase inhibitor that reduces dietary fat absorption and is being developed for weight control in obesity, on the absorption of vitamins A and E. Each participant received a single oral dose of 25,000 IU vitamin A followed 24 hours later by a single oral dose of 400 IU vitamin E on two separate occasions: during oral administration of 120 mg orlistat or placebo three times daily for 9 days. The two treatments were separated by a washout period of at least 2 weeks. Serial blood samples for pharmacokinetic analysis were collected at specified times over 24 hours after each dose of vitamin A for determination of serum concentrations of retinol, and over a period of 5 days after each dose of vitamin E for determination of serum concentrations of alpha-tocopherol, total cholesterol, and triglycerides. Orlistat significantly reduced the absorption of vitamin E (approximately 43% according to maximum concentration and approximately 60% according to area under the concentration-time curve), but not that of vitamin A, at the dose levels studied. The results of this study will aid in the implementation of a vitamin supplementation strategy, should vitamin deficiency occur in patients undergoing orlistat therapy.
authors.affiliation: Hoffmann-La Roche Inc., Nutley, New Jersey 07110-1199, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Melia
authors.forename: S G
authors.initials: SG
authors.lastname: Koss-Twardy
authors.forename: J
authors.initials: J
authors.lastname: Zhi
mesh_terms: D000042:Absorption; D000328:Adult; D018592:Cross-Over Studies; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007783:Lactones / Q000494:pharmacology*; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood*; D008297:Male; D000077403:Orlistat; D014801:Vitamin A / Q000097:blood / Q000493:pharmacokinetics*; D014810:Vitamin E / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D004791:Enzyme Inhibitors; D007783:Lactones; D008055:Lipids; D014801:Vitamin A; D014810:Vitamin E; D000077403:Orlistat