What is Orlistat (Xenical, alli)
Orlistat, also known as tetrahydrolipstatin, a drug designed to treat obesity. Orlistat is marketed by Roche under the trade name Xenical, and as an over-the-counter under the name alli by GlaxoSmithKlinei.
Orlistat is primarily used to prevent the absorption of fats from the human diet, hence reducing caloric intake and should be used in combination with a physician-supervised reduced-calorie diet.
How it works
Orlistat works by inhibiting the break down of triglycerides in the intestine. So triglycerides, in what you eat, are prevented from being made absorbable-free-fatty-acids and are excreted undigested.
At the standard prescription dose of 120 mg three times daily before meals, orlistat prevents approximately 30% of dietary fat from being absorbed. Higher doses do not produce more potent effects.
What Orlistat side effects
The primary side effects of Orlistat are gastrointestinal-related. Side effects are most severe when beginning therapy, and decrease in frequency with time; in clinical trials, nearly half of side effects lasted less than a week, but some may persist for over six months. Because orlistat’s main effect is to prevent dietary fat from being absorbed, the fat is excreted unchanged in the feces and so the stool may become oily or loose (steatorrhea). Increased flatulence is also common. Bowel movements may become frequent or urgent, and rare occurrences of fecal incontinence have been seen in clinical trials. To minimize these effects, foods with high fat content should be avoided; the manufacturer advises consumers to follow a low-fat, reduced-calorie diet. Oily stools and flatulence can be controlled by reducing the dietary fat content to somewhere in the region of 15 grams per meal.
What NOT to take with Orlistat
Absorption of fat-soluble vitamins and other fat-soluble nutrients is inhibited by the use of orlistat. A multivitamin tablet containing vitamins A, D, E, K, and beta-carotene should be taken once a day, at least 2 hours before or after taking the drug.
Orlistat may reduce plasma levels of cyclosporin, an immunosuppressive drug frequently used to prevent transplant rejection; the two drugs should therefore not be administered concomitantly.
Some claims!
Despite claims that orlistat increases the risk of breast cancer amongst clinical trial participants, there is evidence to suggest that the introduction of specific varied preparations containing orlistat, namely the concurrent administration of orlistat and the monoclonal antibody trastuzumab, can actually induce cell death in tumor cells and block their growth.
A 2006 animal study addressed a connection orlistat shares with aberrant crypt foci (ACF), lesions found in the colon which are believed to be one of the earliest precursors of colon cancer.
Orlistat Contraindications
Orlistat is contraindicated in:
- Malabsorption
- Reduced gallbladder function (e.g. after cholecystectomy)
- Pregnancy and breastfeeding
Orlistat availability
In most areas, such as the United Kingdom, France, and Canada, orlistat is available by prescription only. In Australia and the United States, certain formulations of orlistat have been approved for sale without a prescription.
United States
On January 23, 2006, a U.S. Food and Drug Administration advisory panel voted 11 to 3 to recommend the approval of an OTC formulation of orlistat, to be marketed under the name alli by GlaxoSmithKline. Approval was granted on February 7, 2007,and alli became the first weight loss drug officially sanctioned by the U.S. government for over-the-counter use. Consumer advocacy organization Public Citizen, through its Health Research Group, opposed over-the-counter approval for orlistat, calling it “the height of recklessness” and “a dangerous mistake” due to questionable benefits and possible adverse effects.
(Becoming available in the U.S. during the summer of 2007, alli will be sold as 60 mg capsules — half the dosage of prescription orlistat.)
As of 2007, no generic formulations of orlistat are legally available in the United States. U.S. patent protection for Xenical, originally to end on June 18, 2004, was extended by five years (until 2009) by the U.S. Patent and Trademark Office. The extension was granted on July 20, 2002.
Australia
In Australia, orlistat is currently available over-the-counter in 120 mg size (84 capsules to the pack). Initially available only with a prescription, it was reclassified as a “Pharmacist Only Medicine” in October 2003. In late 2006, the Australian Consumers’ Association complained that Roche was inappropriately advertising the drug to teenagers, and Roche was forced to withdraw its ads. The Association filed further complaints with the Therapeutic Goods Administration — TGA, Australia’s regulatory authority for healthcare products — and the TGA’s Scheduling Committee agreed to convene on February 20, 2007, to discuss possible revoking of orlistat’s over-the-counter status. The Committee ultimately decided to keep orlistat as a Schedule 3 drug, but withdrew its authorization of direct-to-consumer Xenical advertising, stating this “increased pressure on pharmacists to provide orlistat to consumers…this in turn had the potential to result in inappropriate patterns of use”.
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