Bariatric Times

APR 2018

A peer-reviewed, evidence-based journal that promotes clinical development and metabolic insights in total bariatric patient care for the healthcare professional

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8 The Medical Student Notebook Bariatric Times • April 2018 Weight Loss Medications for Patients: A Review by MANOJ KANAGARAJ, BS, BA Bariatric Times. 2018;15(4):8–10. ABSTRACT Obesity is among the most common causes of morbidity in the United States. Few patients and providers are aware of effective treatment options for obesity besides bariatric surgery and lifestyle interventions. This review will focus on the use of medications for weight loss in patients with obesity. It will address the indications, options, costs, benefits, and effectiveness of United States Food and Drug Administration (FDA)-approved weight loss medications currently on the market. KEYWORDS Weight loss, drugs, pharmacotherapy, price, medication INTRODUCTION Obesity is one of the most common causes of disability today. In the United States alone, nearly two- thirds of Americans have overweight or obesity. 1 Obesity is also reaching epidemic proportions worldwide as well. 2 Weight loss can help patients with obesity avoid suffering from such medical conditions as heart disease, diabetes, and cancer. 1 It is critical that effective treatment options exist to help patients tackle this problem. Obesity, however, is difficult to treat and often requires multiple therapeutic modalities. The first measures usually involve intensive lifestyle interventions, including strict diet, exercise, and cognitive changes to promote healthy eating and increased activity. Later measures can include a combination of lifestyle intervention and bariatric surgery, which is highly effective for both weight loss and control of associated comorbidities. 3 Few other options exist for patients seeking a bridge between behavioral changes and invasive surgery. Chief among them are pharmacotherapies. Currently, there are six United States Food and Drug Administration (FDA)-approved medications for weight loss. 4 These medicines are primarily intended either as adjuncts to diet or exercise. 5 Weight loss medicines have a notably checkered past. In the 1930s, 2,4-dinitrophenol (DNP) gained considerable popularity for its weight-reducing effects. 6 It works by interfering with the process that creates adenosine triphosphate (ATP). Specifically, DNP uncouples oxidative phosphorylation by increasing the basal leakage of protons across the mitochondrial membrane. This weakens the proton gradient that is necessary to fuel ATP production. The potential energy from the proton gradient is instead lost as heat. Consequently, more calories must be consumed per unit of energy produced. The medicine's weight- loss effect thus came coupled with the side effect of hyperthermia. Many patients presented with hyperthermia, cataracts, tachycardia, diaphoresis, tachypnea, and eventual cardiac arrest. 7 By 1938, the FDA recommended against human usage of DNP. Multiple weight loss compounds have since been studied, some of which have undergone clinical trials and been approved by the FDA for the treatment of obesity. Before prescribing any of these medications to your patients, it is important to consider the risks versus benefits of each in order to determine the safest and most effective medicine for each patient. This review addresses this critical concern in the management of the bariatric patient. INDICATIONS Pharmacologic therapy is indicated for any patient diagnosed with obesity (body mass index [BMI] ≥30). 8 Some patients who are moderately overweight (BMI ≥27) but do not have obesity can use certain weight- loss drugs if they have at least one co-existing condition associated with obesity. These conditions include diabetes, hypertension, hyperlipidemia, and sleep apnea. 9 If the appropriate criteria are met, patients with obesity should be started on these medications when they fail to reach adequate weight loss through lifestyle intervention alone. 4 Importantly, lifestyle intervention must continue even while patients use prescription weight loss drugs. These medicines achieve best results when used as adjuncts to a weight-loss program that is already incorporating increased exercise, behavioral therapy, and calorie-restricting diets. These medications should be discontinued if less than five percent of weight is lost in a 12-week trial. 10 OPTIONS Phentermine. First introduced in 1959, phentermine is the most commonly prescribed weight loss medication. 4 It works to reduce appetite through its sympathomimetic properties. This suppression of appetite helps decrease food consumption and weight gain. A clinical trial in 2013 demonstrated that phentermine monotherapy led to at least five percent weight loss in 43 percent of patients on a low dose formulation and 46 percent on a higher dose formulation. 11 The side effects of the drug are similar to those of other stimulants and include dizziness, anxiety, insomnia, tachycardia, hypertension, diarrhea, or constipation. Notably, phentermine had been historically used in tandem with an anti-obesity medication called fenfluramine that was withdrawn from the market for increasing risk of cardiac valvulopathy in patients. 12 Most of this risk was attributed to the fenfluramine component of the drug combination, leaving phentermine available on the market. Phentermine is approved by the FDA in a lower- dose, 8mg formulation called Lomaira. It is implied that this formulation leads to similar outcomes with reduced side effects based on historical trials, The MEDICAL STUDENT Notebook This column is written by medical students and is dedicated to reviewing the science behind obesity and bariatric surgery. COLUMN EDITOR Daniel B. Jones, MD, MS, FASMBS Professor of Surgery, Harvard Medical School, Vice Chair, Beth Israel Deaconess Medical Center Boston, Massachusetts FEATURED STUDENT Manoj Kanagaraj, BS, BA Medical Student, Harvard Medical School, Boston, Massachusetts

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