A 40-year-old obese man with type 2 diabetes mellitus comes to the clinic complaining of abdominal distension, flatus, and an episode of low-volume fecal incontinence over the past 2 weeks. His last hemoglobin A1C 2 months ago was 7.5%. He has been treated with metformin for years and was recently started on exenatide and orlistat.
His blood pressure is 133/90 mm Hg and pulse is 82/min. Body mass index is 37 kg/m². His abdomen is distended, tympanic, and nontender.
Which of the following is the best next step in management of this patient?

Question

Quizplus · Accepted Answer

This patient's presentation is consistent with adverse effects from the anti-obesity medication orlistat. Orlistat is used for long-term treatment of obesity in patients with body mass index > 30 kg/m²or > 27 kg/m² with comorbidities (eg, diabetes, dyslipidemia, hypertension). The drug inhibits pancreatic lipase to alter fat digestion, decrease fat absorption, and increase fecal fat excretion. As a result, patients with diet fat > 30% of total calories can develop symptoms similar to fat malabsorption disorders (eg, flatus, fecal incontinence, abdominal distension). A low-fat diet (< 30% total fat calories) can reduce these symptoms. < Orlistat can also decrease absorption of fat-soluble vitamins, and patients should take a daily multivitamin. Orlistat-induced fat malabsorption can also increase intestinal calcium binding, which leads to decreased available calcium to bind oxalate. This leads to increased oxalate absorption, increased urinary oxalate excretion, and possible calcium oxalate stones. As a result, orlistat should not be used in patients with history of calcium oxalate stones. (Choice A) Exenatide is a glucagon-like peptide 1 analog that can improve glycemic control and induce weight loss in overweight diabetics. The main side effects are nausea, acute pancreatitis, and acute kidney injury. This patient's absence of nausea, vomiting, and significant abdominal pain makes pancreatitis less likely. (Choice B) Lactose intolerance tends to present with increased bloating, flatulence, crampy abdominal pain, and watery diarrhea after consumption of dairy products. Lactose intolerance can be seen in certain ethnic groups (eg, whites) as they age. It can also be due to bacterial overgrowth, gastrointestinal disease causing intestinal villus flattening, or inflammatory bowel disease. However, orlistat is not associated with lactose intolerance. (Choice D) Metoclopramide is a promotility agent used in delayed gastric emptying. Although patients with this disorder can experience abdominal distension, the majority also complain of nausea and vomiting, abdominal pain, and early satiety, which are not seen in this patient. (Choice E) Although simethicone can help with flatus, excess intestinal gas does not explain the episode of fecal incontinence. Flatulence can also occur frequently with constipation due to stool obstruction causing decreased gas absorption. Educational objective: Orlistat is used for the long-term treatment of obesity. It inhibits pancreatic lipase to reduce fat absorption and increase fecal fat excretion. Patients with fat intake > 30% of total calories can develop side effects similar to fat malabsorption (eg, flatus, fecal incontinence, oily spotting). A lower fat intake can reduce these symptoms. __________ References: Orlistat: a review of its use in the management of patients with obesity. (http://www.ncbi.nlm.nih.gov/pubmed/15563254)

A 40-Year-Old Obese Man with Type 2 Diabetes Mellitus Comes