So, people who are taking Orlistat need to have excess doses of these nutritional materials.

NPR: Slate's Medical Examiner: Xenical OTC

The only FDA-approved weight loss medications are sibutramine (Meridia), orlistat (Xenical), and phentermine.

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Riluzole, a treatment for Motor Neurone Disease, was provided by 94% of authorities, the obesity treatment Orlistat 96% and flu drug Relenza, 96%.

BBC: Drug prescribing methods queried

On Thursday, the Public Citizen Health Research Group petitioned the U.S. Food and Drug Administration to ban the only approved long-term weight-loss drug, orlistat.

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The group said that orlistat, sold in prescription form as Xenical and over-the-counter as Alli, causes serious side effects such as liver injury and kidney failure.

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And that's one theory of the way Orlistat works.

NPR: Slate's Medical Examiner: Xenical OTC

Dr. SPIESEL: Yeah, And we'll talk in a minute about where it might go, but, yeah, that's actually the idea of Orlistat, that if you can't absorb fat then you're going to lose weight.

NPR: Slate's Medical Examiner: Xenical OTC

"There is good evidence for the efficacy of Orlistat (Alli) in weight reduction but it should not be used as the sole element of weight management, " says Dr Colin Cable of the Royal Pharmaceutical Society of Great Britain, who reviewed the products.

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