INTRODUCTION

According to the Centers for Disease Control and Prevention (CDC) National Center for Health Statistics (NCHS) data brief, the prevalence of obesity among adults in the United States was 42.4% in 2017–2018.¹ It contributes to the development of heart disease, stroke, type 2 diabetes, and certain cancers that are the leading causes of preventable, premature deaths. Obesity and its associated health problems significantly affect the cost of health care in the United States. The cost to the entire health care system, estimated at $147 billion in 2008, is more than 10% of the total health care costs in the United States.²³ Not only are medical costs for people with obesity and severe obesity higher than those of normal weights (by 30% and 81%, respectively), indirect costs from lost productivity drive the economic impact of obesity and severe obesity even higher.⁴

Figure 1. Trends in Age-Adjusted Obesity and Severe Obesity Among Adults Aged 20 Years or Older, United States, 1999–2000 Through 2007–2018

Source: NCHS, National Health and Nutrition Examination Survey, 1999–2018
¹ Significant linear trend

Obesity is also a major medical problem outside of the United States. According to the World Health Organization (WHO), worldwide obesity has more than tripled since 1976.⁵ In 2016, an estimated 1.9 billion adults (18 years and older) worldwide were overweight; of these adults, 650 million individuals were obese. Globally, more people are obese and overweight than underweight, with the exception of parts of sub-Saharan Africa and Asia.

Fortunately, overweight or obesity are preventable and treatable conditions. Behavioral modification focusing on dietary and exercise interventions can have a long-term impact on improving and preventing weight-associated diseases, including serious and potentially fatal conditions such as heart disease and diabetes.⁶ Positive support from friends, family, and the community can encourage easier choices for healthier lifestyles and environments to provide the opportunity for physical activities. Several weight loss programs are available that provide group support, counseling, and structured diet plans. The key to choosing a successful diet plan, however, is an individual choice that should be based on the person’s likes, dislikes, and goals so that the person is motivated and willing to follow the plan.⁷

PHARMACOTHERAPY AND DIETARY OPTIONS FOR WEIGHT LOSS

Healthcare professionals can prescribe medications as a tool to improve weight loss while modifying diet and lifestyles. However, most weight-loss drugs can only be used short-term and when combined with diet and exercise for a 12-month period typically result in a 5% to 10% weight loss.⁶ There are two types of weight-loss drugs available: lipase inhibitors and appetite suppressants. Appetite suppressants or anorexiants usually contain stimulants that are controlled substances and can be addictive. Table 1 lists the available weight loss drugs. More recently marketed nonaddictive weight-loss medications that may increase the demand for weight-loss drug therapy are approved for long-term use:

1. Naltrexone hydrochloride and bupropion hydrochloride
2. Liraglutide

Herbal or dietary supplements are commonly advertised and promoted for weight-loss; however, none have been approved by the U.S. Food and Drug Administration (FDA) for weight loss. Many of them have not been adequately studied for effectiveness or safety.⁸ Orlistat is the only OTC product approved for weight loss.

Patients who are prescribed weight-loss medications should meet certain criteria that are generally noted in the labeling of drugs. These are generally indicated for patients with obesity ^{body mass index (BMI) >30 kg/m2) or patients with overweight (BMI >27 kg/m2 ) and the following risk factors: type 2 diabetes, hypertension, hypercholesterolemia, heart disease, stroke risk, and/or sleep apnea.9}

Making changes in diet, exercise, and lifestyle or taking weight-loss medications does not always work for everyone. According to the American Society for Metabolic and Bariatric Surgery (ASMBS), persons with severe obesity are unsuccessful with long-term weight loss by diet and exercise alone, and it is nearly impossible for these people to achieve a normal BMI without metabolic and bariatric surgery.¹⁰ Diet and exercise alone have a high failure rate, with less than a 10% long-term excess weight loss in patients with obesity.^11,12

THE OPTION OF BARIATRIC SURGERY

Bariatric surgery is endorsed by the National Institutes of Health (NIH) and the ASMBS as an effective treatment for morbid obesity and long term weight loss. Dr. Paul O’Brien, an expert in bariatric surgery, has also published studies and articles demonstrating the long-term benefits and is cited by the NIH and ASMBS.^{13, 14} Surgery results in significant weight loss and helps prevent, improve, or resolve more than 40 obesity-related diseases or conditions including type 2 diabetes, heart disease, obstructive sleep apnea, and certain cancers.^15,16,17Studies show surgery reduces a person’s risk of premature death by 30% to40%.^18,19

Bariatric surgery is not the first option for patients who are overweight; however, it is definitely a good, effective, viable option when all other options have failed to produce a healthy weight for the patient. Patients may lose up to 60% of their excess weight 6 months after surgery and 77% of excess weight as early as 12 months after surgery.²⁰ On average, 5 years after surgery, patients maintain 50% of their excess weight loss.²²

There are 3 basic types of bariatric surgical procedures: malabsorptive, restrictive, and a combination malabsorptive/restrictive. In malabsorptive procedures, weight loss is achieved by bypassing certain sections of the small intestine to prevent digestion and absorption of nutrients. Earlier malabsorptive procedures, such as the jejunoileal (JIB) and jejunocolonic bypass, caused severe metabolic, hepatic, and nutritional complications, and are no longer performed today.

Patients experienced electrolyte imbalances, anemia, osteoporosis, irregular diarrhea, gallstones, cirrhosis, arthritis, and other problems.²¹ Because of significant complications of these strictly malabsorptive procedures, only the biliopancreatic diversion with duodenal switch is performed today and reserved for severely obese patients.

Restrictive procedures, primarily used in patients who are moderately obese, reduce only the volume of solid food intake. The stomach of a typical person can hold up to 3 pints of food; after surgery, the stomach may hold as little as an ounce. Depending on the procedure, the stomach may eventually hold up to 5 or 6 ounces of food.^{22, 23}

The first restrictive procedure developed was gastroplasty or “stomach stapling.” It was not very successful because the staple line often ruptured, the surgically created pouch would expand, and the weight would be rapidly regained.

The next available surgery used a commercially available product, the Lap-Band, which was approved by the FDA in 2001. The procedure is done laparoscopically but is rarely performed today because of the high failure rate for weight loss and complications. More recently, the FDA approved in 2016 the gastric balloon, which is a temporary, 6-month treatment option for weight loss and usually used for preoperative bariatric surgery weight loss or for patients that need to help losing weight that do not qualify for bariatric surgery. It is inserted and removed endoscopically as an outpatient procedure. Finally, a permanent restrictive bariatric procedure is the vertical sleeve gastrectomy (VSG), during which 80% of the patient’s stomach is removed.²⁴

Other bariatric surgical procedures combine malabsorptive and restrictive procedures to achieve weight loss in morbidly obese patients. The most common procedure is the Roux-en-Y gastric bypass (RYGB). This procedure is often chosen for patients with type 2 diabetes to minimize carbohydrate and fat consumption; it provides more weight loss than with the VSG, but patients are prone to the “dumping syndrome” adverse effect (Table 2). Although very uncomfortable, patients who have experienced this syndrome use it as a deterrent from eating sugar and fats that can cause dumping syndrome.

NUTRITIONAL STATUS BEFORE BARIATRIC SURGERY

Good nutritional status is a marker for good health. Every person needs to have a minimum amount of protein, carbohydrates, fat, vitamins, and minerals so that the body can perform properly. This can be assessed through laboratory blood draws, food diaries, physical examinations, and patient interviews. Unfortunately, Americans generally consume calorie-dense, nutrient-poor diets that supply fewer than one-half of the Recommended Daily Allowance (RDA) of vitamins and minerals.²⁵ Even though patients with obesity typically consume more calories, they generally remain deficient in vitamins and minerals. Their diets consist of high-calorie, high-carbohydrate, and high-fat foods with very little nutritional value.

Why is this important? When having major surgery, a patient’s nutritional status can affect wound healing, immunity, recovery times, and positive outcomes. Thus, assessing the patient’s preoperative nutritional status provides insight into nutritional deficiencies that will be present after surgery and time to correct these deficiencies through supplements before and after surgery and thereby enhance recovery.

Patients with obesity are often taking medications that can deplete the body of essential vitamins and minerals. Current medications should be reviewed to identify drug-induced nutritional depletion. Good resources for looking up specific medications are the Drug-Induced Nutrient Depletion Handbook or The Nutritional Cost of Drugs.²⁶²⁷

Medications can cause drug-induced nutritional deficiencies through the following mechanisms²⁸:

• Inhibition of nutrient absorption
• Inhibition of nutrient synthesis
• Changes in transport of nutrients across membranes
• Increase or decrease in metabolism of nutrients
• Increase or decrease in excretion of nutrients
• Changes in the body’s ability to store nutrients

Table 3 summarizes some of the drug classes that affect nutrients and lists the depleted vitamins and minerals.

Before surgery, the patient should begin taking a complete multivitamin with iron (not “silver” or geriatric formulas because they do not contain iron), a calcium supplement with vitamin D, and a vitamin B complex supplement. Getting into the routine of taking nutritional supplements also prepares and develops the habit for patients to continue after surgery.

In addition to the vitamin and mineral supplements, most bariatric surgery programs place patients on a high-protein, low-fat, low-carbohydrate diet. This helps patients lose weight before surgery and can reduce glucose as well as the size of the liver in patients with steatohepatitis (fatty liver), which is common in patients with obesity.^{29, 30}

MEDICATIONS AND SUPPLEMENTS MANAGEMENT IMMEDIATELY BEFORE BARIATRIC SURGERY

At specific time intervals before bariatric surgery, certain medications and herbal supplements must be discontinued or held until after the procedure. If patients do not follow instructions regarding certain medications, the surgery may be delayed or canceled.

One month or more before surgery, all oral contraceptives and estrogen products or preparations should be discontinued to reduce the risk of developing blood clots. Alternative nonoral forms of birth control must be used in the perioperative period.

All aspirin products and nonsteroidal anti-inflammatory (NSAIDs) must be discontinued 1 to 2 weeks before surgery to minimize the risk of developing ulcers or bleeding after surgery.³¹ Patients who routinely take these medications for arthritis or joint pain may need to switch to a nonpharmacologic alternative to treat pain and swelling, such as ice packs, heating pads, transcutaneous electrical nerve stimulation (TENS) units, or topical products that are not systemically absorbed. Transdermal creams, gels, and ointments can be compounded to provide alternatives to oral medications.

For patients on aspirin for secondary prevention of blood clots, there are no official standard recommendations to continue or discontinue aspirin before bariatric surgery, although there is evidence that shows that continuing aspirin is not associated with excessive bleeding.³² More studies with well-defined end points are needed to develop a recommendation. In the meantime, the cardiologist and the bariatric surgeon should determine the best course of action for specific patients.

Herbal products may also increase these risks and should also be discontinued at this time; these include gingko, garlic, ginger, and bee pollen. Two days before surgery, all vitamins and omega-3 fish oils or flaxseed oil should be stopped. These supplements can also have an impact on bleeding and clotting.

The patient should consult with the primary care physician, endocrinologist, or cardiologist before surgery to determine when to stop other prescribed medications such as warfarin, clopidogrel, heparin or heparin-like products, and all antidiabetic medications. As determined by the anesthesiologist or other physicians, some maintenance medications, such as antihypertensives, are taken up to the morning of surgery.

IMMEDIATE MEDICATION NEEDS AFTER BARIATRIC SURGERY

In most bariatric surgery programs, many maintenance medications will be discontinued or reduced by the hospitalist when a patient undergoes bariatric surgery. The patient’s body undergoes rapid changes as a result of this intervention, and the need for many medications can change from day to day. During the first few postoperative weeks, patients may be instructed to crush tablets or open and empty the contents of capsules into a liquid if feasible, or switch to an oral liquid dosage form because the patient may be on a liquid, pureed, or soft-food diet to allow the stomach to heal from surgery.³³

Diuretics are generally discontinued to decrease the risk of dehydration following surgery. If hypertensive, the patient may continue to take an angiotensin converting enzyme inhibitor or angiotensin II receptor blocker they were taking before surgery but at a lower dose. It is important, however, for the patient to monitor blood pressure at home because the rapid weight loss could suddenly change or eliminate the need for antihypertensive agents. Doses of these drugs might need to be lowered, or one or more agents might be discontinued.

Since stress of surgery can increase blood glucose levels, the patient may need to continue insulin or other antidiabetic agents. Again, blood glucose levels need to be monitored daily by the patient at home so that doses can be adjusted as needed. These medications may be discontinued in many patients within a couple of months after surgery.

In addition to these deprescribing opportunities, patients frequently need new medications for short-term control of pain, nausea, stomach acid, and for prevention of blood clots. To control abdominal pain, the patient may have a “pain ball” filled with an anesthetic, such as an on-Q pump with lidocaine; a patient may also need oral liquid pain medications, such as hydrocodone or oxycodone, for a couple of weeks postoperatively. Since solid oral dosage forms may be difficult for a patient to take initially, pharmacists who provide services to patients after bariatric surgery should know available alternatives and keep an adequate supply of the oral liquid dosage form. The patients will need these medications immediately upon discharge to maintain their pain control.

Nausea and vomiting are common after bariatric surgery. While the patient has intravenous access, promethazine or parenteral antinausea medications can be given; however, the patient needs to be switched to an oral dosage form, suppository, or compounded transdermal dosage form upon discharge. The best oral dosage forms include oral liquids or oral disintegrating tablets. If the patient has trouble with vomiting, a suppository dosage form or compounded transdermal cream or gel may be the best option. Oral or parenteral promethazine produces profound drowsiness and could impede the patient’s ability to walk; however, promethazine can be compounded using pluronic lecithin organogel (PLO) base, which will provide adequate control of nausea without the profound adverse side effects.

Proton pump inhibitors (PPIs) are prescribed up to 3 months postoperatively to reduce stomach acid production, reduce the risk of developing stress ulcers from surgery, and allow the stomach to heal. Since the patients generally cannot swallow medications that are larger than a Smarties candy, patients may be instructed to open capsules and sprinkle or mix the contents into a soft food such as applesauce, cottage cheese, or yogurt. PPIs, however, have a bitter quinine taste and some patients may not be able to tolerate them, especially if they are already suffering from nausea. Some PPIs are commercially available in a form that can be mixed into an oral liquid before administration or as a tablet that rapidly dissolves in the mouth when taken orally. These products may be a more palatable alternative for patients after bariatric surgery. Most PPIs can also be compounded into oral suspensions. United States Pharmacopeia (USP) Compounded Monographs are available for lansoprazole and omeprazole suspensions.³⁴ These compounded suspensions are usually in an alkaline base, which has the added benefit of immediately neutralizing the existing stomach acid.

A small number of patients (4%) develop gallstones and require a cholecystectomy after bariatric surgery. This risk is highest during the first 6 postsurgical months.³⁵ It is also more common in patients who have gastric bypass surgery than in those who have VSG and band surgery. As a preventive measure, some bariatric surgeons prescribe ursodiol 300 mg twice daily soon after discharge for up to 6 months postoperatively. The commercial ursodiol capsules are large and can be difficult to swallow for some patients. Fortunately, ursodiol can be easily compounded into a palatable oral suspension. A USP compounded monograph is available for this drug.34 Removing a normal and asymptomatic gallbladder during the bariatric surgery as a preventive measure is not recommended by ASMBS. It is not necessary and may put the patient as risk for possible complications without proven benefit.³⁶

While in the hospital, the patient may receive anticoagulants such as enoxaparin as venous thromboembolism (VTE) prophylaxis. Once the patient is mobile and actively walking, VTE can be discontinued.

CHOOSING QUALITY NUTRITIONAL SUPPLEMENTS

After bariatric surgery, patients are forever committed to taking nutritional supplements, including vitamins and minerals. They are not physically able to ingest enough food and absorb all of the necessary nutrients to maintain optimal nutritional status. Initially, patients need to use chewable or oral liquid dosage forms. Soft chews are also acceptable. Gummy dosage forms, however, should not be used because they do not dissolve well and may even cause a blockage in the altered intestinal tract. Generally, all patients who have had bariatric surgery should take the following supplements²⁹:

• Complete multivitamin 2 tablets daily
• Calcium citrate 500 mg 3 times daily (taken with vitamin D to improve absorption)
• B-Complex 1 capsule daily for the first 6 months
• Vitamin B₁₂ 1000 mcg sublingually weekly
• Iron 27–30 mg daily if needed (taken with ascorbic acid to improve absorption)

Note that calcium and iron supplements need to be taken several hours apart from each other because they bind with each other, decreasing absorption. Iron supplements can be taken with the multivitamins. To optimize absorption of each supplement, the patient should take the calcium at least 2–4 hours after taking the iron supplement. At least one dose of the calcium should be taken at bedtime because the body absorbs calcium better during the night. A good regimen to follow is to take the multivitamins, B-complex, and iron supplements in the morning after breakfast to help minimize any nausea and take the calcium supplements after lunch and at bedtime. People cannot absorb more than 500 mg of calcium per dose.

Since absorption of nutrients is altered and even impaired after gastric-bypass surgery, choosing the right nutritional supplement is critical for people to maintain good nutritional status. Vitamins and minerals may have different salt forms or sources, some of which are better absorbed. Table 4 lists the most bioavailable sources or forms for each vitamin or mineral.³⁷

All bariatric surgery weight loss programs emphasize protein as the most important macronutrient in the diet. Typically, most programs require postoperative patients to consume at least 60 grams and up to 1.5 grams/kg of protein daily.30 Protein provides the amino acids required by the body to produce its own proteins, a variety of nitrogen-based molecules, hormones, enzymes, immune system components, and structural components. Proteins also help to maintain fluid and acid-base balance in the body.

There are basically two sources of dietary protein: animal and plant. Protein source is an individual patient choice. Animal-based protein is a complete protein. In other words, it contains all of the essential and nonessential amino acids that people require, and it is easily absorbed. Sources for animal-based protein include dairy (whey), cheese, eggs, fish, and meat. Most plant-based protein is an incomplete protein meaning it is missing an essential amino acid.³⁸ Some plant-based protein may be more difficult for people to digest. However, a plant-based diet is possible after bariatric surgery. Common plant-based proteins include soybeans, peas, quinoa, lentils, various nuts, seeds, and other legumes. After surgery, some patients may develop intolerance to whey protein and therefore cannot use dairy products. Other patients may develop intolerance to soy protein and may have to use pea-based protein.

Some protein supplements are better and more easily absorbed than others, but how can one decide which supplement is high quality and bioavailable? A few scoring methods are available to evaluate protein quality: amino acid scoring (also called chemical scoring), biological value, net protein utilization, and the Protein Digestibility Corrected Amino Acid Score.³⁹ Pharmacists or bariatric team members — possibly assisted by a nutritionist or registered dietitian — should review protein supplements using the above listed scoring methods before providing recommendations to the patient.

As patients evaluate their protein choices, pharmacists or bariatric team members may be able to help balance taste preferences with palatability, tolerability, and other factors. Pharmacies or wellness centers that service bariatric patients should carry a medical-grade protein supplement line and possibly have a sampling event or a cooking event to sample recipes prepared with the supplements. Vendors for medical-grade protein and bariatric supplements can be a good source of information for health care professionals to provide guidance in choosing quality supplements to meet the needs of bariatric patients.

ADJUSTING PHARMACOTHERAPY AFTER BARIATRIC SURGERY

Medications go through several processes in the human body: dissolution, absorption, distribution, metabolism, and excretion. Since these processes are studied in people with intact gastrointestinal tracts; depending on the type of bariatric surgery or procedure, some or all of these processes can be significantly affected.^40,41,42,43

Dissolution is affected by nearly all of the bariatric surgeries and procedures. Numerous drugs require dissolution by the GI fluids. Most drugs are acidic, and the hydrochloric acid produced by the stomach dissolves these drugs into into its absorbable, ionized form. After bariatric surgery, patients’ production of hydrochloric acid is significantly decreased, and the pH of the gastric fluids increases and become more basic. Gastric volume is reduced, with less fluid to dissolve solid oral dosage forms. This can decrease and/or delay absorption of drugs by the body. Acidic drugs that may be affected by decreased dissolution include rifampin, digoxin, simvastatin, ketoconazole, carbamazepine, selegiline, iron supplements, and warfarin. Decreases in absorptive areas of the intestines and intestinal enzyme production can also impair drug absorption.⁴³

Patients who have had RYGB surgery have additional problems with dissolution because of changes in the small intestines. From the stomach, the drug travels to the upper small intestine that includes surfactants from pancreatic and bile secretions that further aid in the dissolution of drugs. Following RYGB surgery, the bile secretions are released in distal sections of the intestines. The dissolution and absorption of drugs that are highly lipophilic may be delayed or impaired in patients following RYGB surgery. Lipophilic drugs may be affected by this change, including cyclosporine, phenytoin, rifampin, and levothyroxine.

Many drugs are absorbed in the small intestines after dissolution by passive transfer through the epithelial membrane and into the intestinal wall. This process is pH-dependent. The anatomical changes in the RYGB surgery may significantly reduce drug absorption secondary to reduced intestinal transit time and intestinal wall surface area. This may not be as significant after VSG since the intestines are not altered; however, the pH still may be increased, which can have an effect on passively absorbed drugs.

Other drugs require active transport via carrier proteins, and these are usually concentrated in the upper intestines. Since these are removed or altered in RYGB or other gastric bypass procedures, absorption of these drugs is reduced. One of the main active enzymes involved in metabolism of drugs is cytochrome P450 enzyme 3A4, and it is highly concentrated in the upper small intestines. Metabolism of drugs can be reduced, resulting in higher serum concentrations.

Disintegration of solid oral dosage forms can be substantially reduced by restrictive bariatric procedures, since gastric actions and secretions are reduced. Because of this, oral liquid dosage forms are preferred since they eliminate the disintegration problem. Coated tablets often require crushing to release active drug(s) and thereby aid dissolution. Extended- or sustained-release products should not be used in patients following bariatric surgery because of the unpredictability of dissolution and absorption.

Gastric emptying can be reduced by bariatric surgery, possibly reducing the rate of drug absorption. This concept is theoretical and has not been demonstrated in studies. Bariatric surgeries that bypass the duodenum and the proximal jejunum may be problematic for drugs with poor water solubility, as they may not have adequate transit time for dissolution and absorption.

The absorption of highly lipophilic drugs is more likely to be affected because they require bile acids to enhance solubility. Drugs affected include cyclosporine, phenytoin, rifampin, levothyroxine, and tacrolimus. All of these drugs, except tacrolimus, undergo enterohepatic recirculation.

Since patients often lose more than 100 pounds of adipose tissue or “fat” after bariatric surgery, the pharmacokinetics of lipid-soluble drugs with a large volume of distribution (V_d) that readily cross cell membranes can be affected. With the loss of adipose tissue, drugs with large V_d such as fluoxetine can shift into other compartments such as plasma, interstitial fluid, intracellular fluid, and transcellular fluid.

Drugs with a small V_d, such as lithium, may require lower maintenance doses because of the decreased glomerular filtration following weight loss.

Drugs with a narrow therapeutic index should be monitored through serum levels in patients after bariatric surgery. A preoperative baseline serum level should be performed to aid the practitioner in assessing postoperative relapses or symptoms.⁴⁴

Table 5 summarizes the effects of bariatric surgery on absorption for certain drugs. Even though absorption can be reduced by bariatric surgery,⁴⁶ compensatory mechanisms can allow drugs to be adequately absorbed for therapeutic effect, but further study of this phenomenon is needed.

CONCLUSION

Providing care to patients following bariatric surgery can be a challenge for pharmacists. The patients have altered anatomy that can affect absorption of nutrients and drugs. To provide full support as part of an interprofessional bariatric surgical care team, pharmacists must be knowledgeable about the surgical procedures and patients’ nutritional and medication needs.

References

1. National Center for Health Statistics. Prevalence of obesity and severe obesity among adults: United Sates, 2017–2018. NCHS Data Brief No. 360, February 2020. Available at: https://www.cdc.gov/nchs/products/databriefs/db360.htm. Accessed on: February 25, 2020.
2. Tremmel M, Gerdtham UG, Nilsson PM, Saha S. Economic burden of obesity: a systematic literature review. Int J Environ Res Public Health. 2017;14(4):435.
3. Trogdon JG, Finkelstein EA, Feagan CW, Cohen JW. State- and payer-specific estimates of annual medical expenditures attributable to obesity. Obesity (Silver Spring). 2012;20(1):214–220.
4. 4. Xia Q, Campbell JA, Ahmad H, Si L, de Graaff, B, Palmer AJ. Bariatric surgery is a cost‐saving treatment for obesity—a comprehensive meta‐analysis and updated systematic review of health economic evaluations of bariatric surgery. Obesity Rev. 2020;21(1):e12932.
5. 5. World Health Organization. Obesity and overweight fact sheet. Available at: https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight. March 3, 2020. Accessed on: April 25, 2020.
6. 6. S. Department of health and Human Services. Nutrition, Physical Activity, and Obesity. 2020. Available at: https://www.healthypeople.gov/2020/leading-health-indicators/2020-lhi-topics/Nutrition-Physical-Activity-and-Obesity. Accessed on: May 8, 2020.
7. 7. Mechanick JI, Apovian C, Brethauer S, et al. Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures — 2019 update: cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic & Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists — executive summary. Endocr Pract. 2019;25(12)1346–1359.
8. 8. Maunder A, Bessell E, Lauche R, Adams J, Sainsbury A, Fuller NR. Effectiveness of herbal medicines for weight loss: a systematic review and meta-analysis of randomized controlled trial. Diabetes Obes Metab. 2020:22:891–903.
9. 9. Anderson L. Prescription weight loss/diet pills: what are the options? Drugs.com. April 13, 2018. Available at: https://www.drugs.com/article/prescription-weight-loss-drugs.html. Accessed on: April 25, 2020.
10. 1 American Society for Metabolic and Bariatric Surgeries. Bariatric surgery misconceptions. Available at: http://asmbs.org/patients/bariatric-surgery-misconceptions. Accessed on: February 25, 2020.
11. 1 Klein S. Medical management of obesity. Surg Clin North Am. 2001;81:1025–1038.
12. 1 Skender ML, Goodrick GK, Del Junco DJ, et al. Comparison of 2-year weight loss trends in behavioral treatments of obesity, diet, exercise, and combinations interventions. J Am Diet Assoc. 1996;96:342–346.
13. 1 O’Brien PE. Bariatric surgery: mechanisms, indications, and outcomes. J Gastroenterol Hepatol. 2010;25(8):1358–1365.
14. 1 O’Brien PE, Hindle A, Brennan L, et al. Long term outcomes after bariatric surgery: a systematic review meta-analysis of weight loss at 10 or more years for all bariatric procedures and single-centre review of 10-year outcomes after adjustable gastric banding. Obes Surg. 2019;21(1):3–14.
15. 1 Chikunguwo S, Dodson PW, Meador PG, et al. Durable resolution of diabetes after roux-en-y gastric bypass associated with maintenance of weight loss. Surgy Obes Relat Dis. 2009;5(3):S1.
16. 1 Kaplan LM. Body weight regulation and obesity. J Gastrointestinal Surg. 2003;7(4):443–451.
17. 1 Kokkinos A, Alexiadou K, Liaskos C, et al. Improvement in cardiovascular indices after roux-en-y gastric bypass or sleeve gastrectomy for morbid obesity. Obes Surg. 2013;23(1):31–38.
18. 1 Sjöström L, Narbro K, Sjöström D, et al. Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl J Med. 2007;357:741–752.
19. 1 Adams TD, Gress RE, Smith SC, et al. Long-term mortality after gastric bypass surgery. N Engl J Med. 2007;357:753–761.
20. 2 Wittgrove AC, Clark GW. Laparoscopic gastric bypass, roux-en-y — 500 patients: technique and results, with 3–60 month follow-up. Obes Surg. 2000;10(3):233–239.
21. 2 Griffen WO, Bivins BA, Bell RM. The decline and fall of the jejunoileal bypass. Surg Gynecol Obstet. 1983;157(4):301–308.
22. 2 Bevan J. Handbook of Anatomy and Physiology. New York: Simon & Schuster; 1978: 45.
23. 2 American Society for Metabolic and Bariatric Surgery. Bariatric Surgery Procedures. Available at: https://asmbs.org/patients/bariatric-surgery-procedures. Accessed on: May 29, 2020.
24. 2 American Society for Metabolic and Bariatric Surgery. Story of Obesity Surgery. January 2004. Available at: https://asmbs.org/resources/story-of-obesity-surgery. Accessed June 26, 2020.
25. 2 Jacques J. Chapter 1: Nutritional Deficiency in Obesity. In: Micronutrition for the Weight Loss Surgery Patient. Edgemont, PA: Matrix Medical Communications; 2006.
26. 2 Pelton R, LaValle JB, Hawkins EB, Krinsky D. Drug-Induced Nutrient Depletion Handbook. Lexi-Comp; 2001.
27. 2 Pelton R, LaValle JB. The Nutritional Cost of Drugs: A Guide to Maintaining Good Nutrition While Using Prescription and Over-the-Counter Drugs. 2nd ed. Morton Publishing Co.; 2004.
28. 2 Robins J. Counseling your patients on drug-induced nutritional depletion and vitamin supplementation. American College of Apothecaries Annual Conference and Expo 2018. Jacksonville, Florida. March 2, 2018.
29. 2 Parrott J, Frank L, Rabena R, Craggs-Dino L, Isom KA, Greiman L. American Society for Metabolic and Bariatric Surgery integrated health nutritional guidelines for the surgical weight loss patient 2016 update: micronutrients. Surg Obes Relat Dis. 2017;13:727–741.
30. 3 Dagan SS, Goldenshluger A, Globus I, et al. Nutritional recommendations for adult bariatric surgery patients: clinical practice. Adv Nutr. 2017;8:382–394.
31. 3 Katkhouda N, Mason RJ, Wu B, et al. Evaluation and treatment of patients with cardiac disease undergoing bariatric surgery. Surg Obes Relat Dis. 2012;8:634–640.
32. 3 Sahebally SM, Healy D, Coffey HJ, Walsh SR. Should patients taking aspirin for sedondary prevention continue or discontinue the medication prior to elective, abdominal surgery? Best evidence topic (BET). Int J Surg. 2014;12:16–21.
33. 3 American Society of Metabolic and Bariatric Surgery (ASMBS). Life After Bariatric Surgery. Available at: https://asmbs.org/patients/life-after-bariatric-surgery. Accessed on: June 19, 2020.
34. 3 The United States Pharmacopeial Convention. USP on Compounding. In: Section 4 Compounded Preparation Monographs. USP 42 – NF 37 (through second supplement). Rockville, MD. 2019.
35. 3 Kellani ZM, El Djouzi S, Kuwada TS, et al. The incidence and timing of cholecystectomy after bariatric surgery. Carolinas HealthCare System. Poster Presentation P503. 2012. Available at: http://www.sages.org/wp-content/uploads/posters/2012/40108.jpg. Accessed on: February 25, 2020.
36. 3 American Society for Metabolic and Bariatric Surgery. Five Things Physicians and Patients Should Question. Choosing Wisely. 2019. Available at: https://www.choosingwisely.org/societies/american-society-for-metabolic-and-bariatric-surgery/. Accessed on: June 19, 2020.
37. 3 Siefert W. Thriving in the business of nutrition: taking your business to the next level. American College of Apothecaries 2016 Fall Conference. St. Louis, Missouri.
38. 3 Anonymous. 13 Nearly Complete Protein Sources for Vegetarians and Vegans. Healthline. Available at: https://www.healthline.com/nutrition/complete-protein-for-vegans. Accessed on: June 26, 2020.
39. 3 Jacques J. Chapter 61. Protein basics. In: Rosenthal RJ, Jones DB, eds. Weight Loss Surgery: A Multidisciplinary Approach. Edgemont, Pennsylvania: Matrix Medical Communications; 2008.
40. 4 Carpenter M, Pisano ME, Bland CM. Implications of bariatric surgery on absorption of nutrients and medications. US Pharm. 2016;41(12):HS2-HS8.
41. 4 Padwal R, Brocks D, Sharma AM. A systematic review of drug absorption following bariatric surgery and its theoretical complications. Obes Rev. 2010;11:41–50.
42. 4 Darwich AS, Henderson K, Burgin A, et al. Trends in oral drug bioavailability following bariatric surgery: examining the variable extent of impact on exposure of different drug classes. Br J Clin Pharmacol. 2012;74(5):774–787.
43. 4 Geraldo MSP, Fonseca FLA, Gouveia MRFV, Feder D. The use of drugs in patients who have undergone bariatric surgery. Int J Gen Med. 2014;7:219–224.
44. 4 McAlpine DE. Pearls: how to adjust drug dosing after bariatric surgery. Curr Psychiatry. 2006;5(1):27–28.

Back to Top