Marketed by GlaxoSmithKline, Alli's generic name is orlistat. Orlistat has been dogged by controversy since it came on the market in 2007. In 2010, the U.S. Food and Drug Administration demanded new product warnings because of the potential for liver failure. Although the FDA noted that this was very rare, it felt additional warnings were merited. Other possible issues include an increased risk of kidney stones in some people.
Orlistat
Orlistat is lipase inhibitor. Lipase is an enzyme that breaks down fat. Lipase inhibitors work by preventing dietary fats from being broken down and absorbed in the intestines. A review of the literature appearing in the "Cochrane Database Systematic Review" shows that patients who followed low-calorie diets and took orlistat lost 2.9 percent more weight than patients who merely followed a low-calorie diet. The most common side effects of orlistat are related to bowel movements. Patients may have increased bowel movements, oily or fatty stools or difficulty controlling their bowels.
Kidney Stones
Kidney stones form when the urine contains too much of certain crystalline materials. The most common kidney stones are formed from calcium and oxalates. Oxalates are a class of small, negatively charged chemicals found in foods such as grapefruit juice, colas, berries, beats, tea, beans, spinach, chard and chocolate.
Research
Research published in the January 2004 "Kidney International," showed that rats fed a high-fat diet or one rich in oxalate had higher urinary oxalate if they were also given orlistat. This increases the risk of kidney stone formation. Authors of a review article appearing in the 2010 "Renal Failure" concurred with this opinion, noting orlistat administration increased the risk of renal stone disease in a small number of individuals. Patients with chronic kidney disease were at highest risk of this side effect.
Recommendation
MedlinePlus suggests you inform your doctor if you have a history of kidney stones before taking Alli. This is sensible advice because people who get calcium oxalate type kidney stones once tend to get them again. Given that Alli is not a magic cure for weight loss, making a modest effort at diet and exercise will more than compensate for not taking this drug.
References
- MedlinePlus: Orlistat
- "Kidney International"; Fat Malabsorption Induced by Gastrointestinal Lipase Inhibitor Leads to an Increase in Urinary Oxalate Excretion; R.R. Ferraz, et al.; August 2004
- "Renal Failure"; Orlistat and Calcium Oxalate Crystalluria: An Association that Needs Consideration; M.H. Ahmed; 2010
- "Cochrane Database Systematic Review"; Long-Term Pharmacotherapy for Obesity and Overweight; R. Padwal, et al.; 2004
- PubMedHeath: Kidney Stones
- National Institute of Diabetes and Digestive and Kidney Diseases; Diet for Kidney Stone Prevention; May 2009
