Following the withdrawal of sibutramine (Reductil) in Europe in January 2010, orlistat-containing diet pills are the only EMEA-approved weight loss drugs available for obesity treatment . In addition, sibutramine's withdrawal from the US market in October 2010, where it was marketed as Meridia, leaves just two types of FDA-approved weight loss drugs available - those containing orlistat or phentermine.
Orlistat diet pill is available in prescription form as Xenical, and over-the-counter (OTC) as Alli. The purpose of this article is to inform patients of this alternative weight loss drug option available.
What is the Weight Loss Drug Orlistat (Xenical, OTC Alli)?
Orlistat is a lipase inhibitor, which means it acts to block the enzymes that break down fat in the gastrointestinal tract. As such, the diet pill induces weight loss by blocking fat absorption by the body. However, orlistat does not block all fat in the diet from being absorbed, and about 75% of the fat taken in still gets digested by the body.
Clinical studies have shown greater than 100% more weight loss when patients are treated with Xenical in combination with diet, compared to just diet alone. The efficacy of Alli for inducing weight loss, however, is around half of that seen for Xenical plus diet.
Diet Pill Orlistat Side Effects
Unlike other diet pills sibutramine and phentermine, there is minimal absorption of orlistat into the bloodstream and the weight loss drug is therefore not associated with the systemic side effects that plight these appetite suppressants. However, because of orlistat’s mode of action, the weight loss drug is associated with side effects that include flatulence, diarrhoea, oily spotting and loose oily stools.
How is Orlistat (Xenical, OTC Alli) Used for Weight Loss or Obesity Treatment?
Orlistat is available in prescription form as Xenical and over-the-counter as Alli. Xenical has been available as a weight loss drug in both the USA and Europe for over a decade now; however, the switch to the OTC version of Alli occurred only in the last few years.
Both weight loss drug options are approved as obesity treatments in patients with a body mass index ( BMI) greater or equal to 30kg/m², or for weight loss in overweight patients (BMI > 28kg/m² in Europe or BMI > 27kg/m² in USA) with associated risk factors, such as type 2 diabetes or dyslipidaemia, when used in conjunction with a reduced-calorie diet.
Although OTC Alli is half the dose of Xenical, each weight loss drug is to still be taken as one capsule three times daily.
What are the Main Differences Between Xenical and OTC Alli Diet Pills?
There are several differences to be noted between Xenical and Alli diet pills, which are as follows:
- Xenical is the prescription version of orlistat, while Alli is available as an OTC diet pill.
- While Xenical is manufactured by Roche, GSK owns the rights to and markets the OTC version.
- Alli contains 60mg of orlistat, while Xenical contains 120mg orlistat.
- Although OTC Alli has been shown to be clinically effective for weight loss when used in conjunction with diet in both overweight and obese patients, Xenical has superior efficacy for weight loss than Alli.
- Due to the lower dose of orlistat in OTC Alli, this weight loss drug has milder side effects than Xenical.
- Xenical has the advantage of having been shown in clinical trials to reduce the onset of diabetes in obese patients.
Problems When Taking OTC Alli or Xenical as a Weight Loss Drug
For weight loss to occur with either weight loss drug, patients much take either Xenical or OTC Alli in combination with a reduced-calorie diet. It is suggested that the diet should contain no more than 30% of calories from fat. Patients must remember to stick to this diet, as the more fat that is ingested, the more likely orlistat side effects will occur.
If patients become worried or disenchanted because of the unpleasant effects associated with diet pills Alli or Xenical, they should remember that these side effects will generally occur at the beginning of treatment, and should become less frequent and go away with time.
Both Alli and Xenical are contraindicated in some patients, therefore if considering the switch to either weight loss drug, overweight and obese patients should consult their pharmacist or doctor to find out whether they are suitable candidates for such options.
Readers may also be interested in the following article:
Sibutramine Ban Will Influence New Obesity Drugs
Sources:
EMEA 2009, ‘European Public Assessment Report (EPAR), Alli', April 2009
GSK 2009, ‘GlaxoSmithKline receives European Commission approval to market alli® (orlistat 60mg)’ , 21 January 2009
Xenical 2009, ‘Xenical Product Information’
Christine Redmond - My interest in science and healthcare has seen me working in the laboratory with tiny cells and DNA to helping set up a cancer clinical ...
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