Pharmacists in many practice settings can play a key role in managing chronically obese patients who undergo bariatric surgery to lose excess weight, said Katie S. McClendon, PharmD, BCPS, a clinical pharmacist at the University of Mississippi Medical Center’s West Jackson Family Medicine Center, in Jackson.
“Obesity is one of those chronic conditions that pharmacists in both inpatient and outpatient settings can have a big impact,” Dr. McClendon said. “I’m an outpatient ambulatory care pharmacist, but hospital pharmacists may be involved before surgery in selecting appropriate antibiotics, in venous thromboembolism (VTE) prophylaxis and in adjusting diabetes control.”
Pharmacists in both settings also can be helpful, she said, in controlling the chronic conditions and risk factors that increase a surgical patient’s chances of an adverse event—not just type 2 diabetes but also high blood pressure, elevated cholesterol level and smoking.
Dr. McClendon was one of several experts contacted by Pharmacy Practice News regarding their strategies for contributing to the care of bariatrics patients. They noted that such care does not focus solely on bariatric surgery interventions, but also on the array of available pharmacologic and other treatment options, including lifestyle modifications, that can help overweight and obese patients achieve their weight loss goals before electing surgery, including the two newest medications, lorcaserin (Belviq, Eisai) and phentermine/topiramate (Qsymia, Vivus).
Although these drugs have proven effective in inducing significant weight loss in some overweight and obese patients, both carry warnings about increased risks for cardiovascular-related and other adverse events. Qsymia, in fact, comes with a Risk Evaluation and Mitigation Strategies (REMS) requirement relating to the known teratogenic potential of one of its two components, topiramate. It can be dispensed only by certified pharmacies. Belviq has a Pregnancy X warning.
“These medications do have safety concerns,” Dr. McClendon said. “We want to be thoughtful of that, but not to the extent that we don’t remember that they may be appropriate for some of our patients who need additional tools to help them be successful in their weight loss.”
Reducing the Risk
Pharmacists can help to reduce the risks of these drugs, according to Kathryn Hurren, PharmD, BCACP, a clinical pharmacy specialist in the Department of Ambulatory Care, VA Ann Arbor Healthcare System, in Michigan. “Pharmacists can screen patients for potential contraindications to these medications before dispensing,” she noted. “Pharmacists with access to laboratory information can ensure that no drug-related laboratory abnormalities are occurring, especially with Qsymia. Avoiding significant drug interactions is very important with these medications. For example, lorcaserin is serotonergic and should not be used with other serotonergic medications, such as [selective serotonin reuptake inhibitors].”
Despite the potential of these newer weight loss treatments and other older ones, bariatric surgery may be the only answer for obese patients who fail to lose weight and face the prospect of multiple comorbidities and premature death. According to the Centers for Disease Control and Prevention, the prevalence of obesity has increased steadily over the past decade, from 30.3% of adults aged 20 years or older in 1999-2000 to 35.9% by 2010 ( Despite this magnitude, only a small percentage of obese patients choose to undergo bariatric surgery. The American Society for Metabolic and Bariatric Surgery estimates that only about 160,000 bariatric procedures were performed in the United States in 2010 (
Area of Growth for Pharmacists 
At the University of Washington Medical Center’s Level 1 Bariatric Surgery Center, approximately 175 to 200 procedures are performed each year, according to Lingtak-Neander Chan, PharmD, an associate professor at the University of Washington School of Pharmacy and specialist for the University of Washington Medical Center bariatric surgical department. Dr. Chan said because of his faculty duties, his role on the surgical team is mostly on a consulting basis. “I know that most bariatric surgery centers don’t have a full-time or even part-time pharmacist,” he told Pharmacy Practice News. “Certainly, that is one area where we hope to see more pharmacists.”
Dr. Chan said there was a lot that pharmacists can do “before and especially after bariatric surgery” to help ensure optimal outcomes. For example, he said, “Our research as well as others have shown that the absorption pattern of medications change,” he said, “and so the same drug given as a liquid may get absorbed very quickly and achieve a very high blood level. And we have patients who clearly experience adverse reactions, and we have to modify their regimen.”
In addition, he said, patients taking extended-release tablets may find that medications get stuck, and they have to be converted to immediate-release doses that need to be given several times per day. “And some patients will have the doses readjusted to maximize the treatment benefits,” he said.
“Ideally, we want to convert some of these medications or dosage forms at least a couple of weeks prior to surgery,” he said, “so a patient doesn’t have to have everything new from scratch; and of course in some cases, there will also be insurance coverage issues, so you want them all resolved prior to surgery.”
Dr. Hurren addressed additional factors that can affect patient outcomes following surgery. “Depending on the procedure,” she noted, “bariatric surgery patients may have decreased surface area, increased gastric pH, decreased gastric emptying, bypassed active drug transporters and altered first-pass metabolism and enterohepatic recycling. There are limited data regarding the pharmacokinetic changes for specific medications. Instead, anticipating potential changes requires an understanding [of] how the pharmacokinetic properties of the medication and the anatomical changes of the procedure will interact. Pharmacists can assist in therapeutic drug monitoring and determining optimal dosage forms.”
Furthermore, she noted, “Patients who have had bariatric surgery require a chronic regimen of vitamins and minerals to avoid deficiencies and related complications, such as anemia and osteoporosis. Bariatric surgery often permits reduction or even discontinuation of drugs for chronic obesity-related diseases, including type 2 diabetes mellitus, hypertension and dyslipidemia. Pharmacists are the optimal providers to anticipate, monitor for and manage potential pharmacokinetic changes of oral medications resulting from the changed anatomy.”
Ongoing Drug Management Challenge
Part of the medication therapy education that bariatric surgery patients require can be done by hospital pharmacists at discharge, but monitoring a patient’s progress is a permanent requirement. “You have received a surgery that has changed your anatomy forever,” Dr. Chan said, “so you are basically going to have a lifelong lifestyle change. Along the line of some of the comorbidities, the surgery would drastically change their insulin requirement, blood sugar control, serum lipids and blood pressure. So, shortly after surgery, these medications have to need to be readjusted. If they are followed closely by the primary care provider, that’s great,” he said, “but if a patient lives in a more remote area, that’s another area where pharmacists can play a role. 
“Patients go to a pharmacy where they can have some of these physical signs and symptoms monitored, and the results can be referred back to their primary care provider for dose adjustment.”
Dr. Chan added, “We have patients who live 150 miles from the university medical center, so they don’t fill their medication prescriptions here; they go back to their local pharmacies. So, there should be some coordination to make sure [the] local pharmacy actually carries in liquid or other special dosage forms.”