Orlistat adverse effects

Orlistat, a semisynthetic derivative of lipstatin, is a potent and selective inhibitor of pancreatic lipases. It was designed to treat obesity. Orlistat prevents approximately 25% of dietary fat from being absorbed. Very little of the drug itself is absorbed. Its adverse effects are therefore restricted to those related to fat malabsorption, with potential losses of fat-soluble vitamins. It has a relatively small effect on body mass, but enough to realise in one study a 37% reduction in the incidence of type 2 diabetes. 

Regrettably, the pharmacologist must confess that no drugs exist that can be recommended for the purpose of weight reduction. The so-called appetite suppressants (anorexiants) act only, if at all, for a limited period and are fraught with side effects. Most anorexiants are derivatives of metham-phetamine that have been withdrawn from the market. A different mechanism of action is involved in the case of an inhibitor of pancreatic lipase, which is required in the intestines for fat absorption. This inhibitor (orlistat) diminishes fat absorption so that fats reach the lower bowel, where they can cause disturbances flatulence, steatorrhea, and frequent need to relieve the bowels occur in about 30% of affected subjects. These symptoms correspond exactly to those seen in pancreatic hypofunction which are then usually treated with pancreatic lipase. Before an obese person submits to treatment with orlistat, he or she should voluntarily reduce the food fat content by one half to live free of such unpleasant adverse effects. 

Orlistat is a pentanoic acid ester that binds to and inhibits gastric and pancreatic lipases the resulting inhibition of their activity prevents the absorption of about 30% of dietary fat compared with a normal 5% loss. Weight loss is due to calorie loss but drug-related adverse effects also contribute by diminishing food intake. The drug is not absorbed from the alimentary tract. 

A single case report suggests that the concurrent use of orlistat and sucrose polyesters (Olestra - used in some foods as a fat substitute) can result in additive gastrointestinal adverse effects (soft, fatty/oily stools, increased flatus and abdominal pain). In the case in question, symptoms resolved when the patient stopped eating Ofesfra-containing food while continuing to take orlistat. ... 

The effect of orlistat in adolescent patients has been evaluated recently. In a group of 12- to 16-year-old individuals, orlistat (120 mg three times daily) in combination with diet, exercise, and behavior modification exhibited minimal weight increase after 1 year (0.53 kg) compared with placebo-treated patients (3.14 kg). Common adverse reactions observed were fatty or oily stools, oily spotting, oily evacuation, or abdominal pain and/or flatulence with bowel movements. Soft stools, nausea, increased defecation, and fecal incontinence also were noted. Orlistat may be better suited for prevention of weight gain in tolerant adolescents, but more studies are warranted before providing a solid recommendation.36... 

The safety and efficacy of orlistat have not been determined beyond 4 years of use. Minimal systemic effects exist because orlistat acts locally in the GI tract. Thus, common side effects reported include oily spotting, flatus with discharge, fecal urgency, fatty/oily stools, oily evacuation, increased defecation, and fecal incontinence.31 Other adverse events include bloating, abdominal pain, dyspepsia, nausea, vomiting, diarrhea, and headache.37... 

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