Implications of Bariatric Surgery on Absorption of Nutrients and Medications

Mary Carpenter, PharmD; Mary Ellen Pisano, PharmD; Christopher M. Bland, PharmD, BCPS, FIDSA


US Pharmacist. 2016;41(12):HS-2-HS-8. 

In This Article

Bariatric Procedures

Currently, bariatric procedures are the most successful and durable treatment for obesity.[3–6] The number of bariatric procedures performed in the U.S. has increased significantly from an estimated 16,000 procedures performed annually in the early 1990s to approximately 179,000 in 2013.[7,8]

The three bariatric procedures primarily performed in the U.S. are laparoscopic adjustable gastric banding (LAGB), laparoscopic sleeve gastrectomy (LSG), and laparoscopic Roux-en-Y gastric bypass (RYGB).[2] Bariatric surgery achieves weight loss by altering the anatomy of the gastrointestinal (GI) tract via restrictive and/or malabsorptive mechanisms. Restrictive procedures achieve weight loss by limiting the volume of food intake while diminishing the stomach's capacity. Malabsorptive procedures achieve weight loss by surgically bypassing regions of the small intestine and diverting biliopancreatic secretions, which limit nutrient absorption.[9] The various procedures are summarized in Table 1.[9–14]

Due to the increased prevalence of obesity and use of bariatric surgery worldwide, it is crucial that pharmacists and healthcare providers have a better understanding of nutrient and medication malabsorption in the post–bariatric surgery population. RYGB is the most frequently performed bariatric procedure in the U.S. and is associated with more pharmacologic/metabolic concerns when compared to other procedures. Thus, the purpose of this article is to review the effects of bariatric surgery, particularly RYGB, on supplement and medication malabsorption.